To get started is a conversational variant of to start. It has the shade of meaning of beginning to work on some task that is going to take some time.

To hold somebody up means to delay them. It's more often used in the passive form, to be held up (by something).

… said to (do something) is a colloquial form of … told me (or him / her / us / them) to (do something); for example, The boss said to leave the boxes here, that is, The boss told us to leave the boxes here.

Come / go along (to somewhere) is a conversational variant of come / go (to somewhere). It has the shade of meaning of joining in some social or group activity.

To get rid of (something / somebody) is a colloquial expression that describes taking some action to remove something or somebody from some particular context. The context may be a physical space or a social situation. For example, These chairs are very old. I think I'll just get rid of them and buy some new ones. Or, A man came to the door, trying to sell me some new windows. It took me ages to ?get rid of him.

To be saddled with (doing) something means to be given some task that is generally unpleasant or tiresome. The image comes from the context of horses. To saddle a horse means to place the saddle (a leather seat for horse riders) on the horse. In other words, you are giving the horse something heavy to carry, which might be heavy.

Tricky is a colloquial word for difficult or complicated.

What is (someone) like? is a rhetorical question (a question that expresses an idea and does not expect an answer) that we use in situations where we find someone's behaviour remarkable in some way. It conveys the meaning, Have you ever met such a person?

To put up with is a phrasal verb that means to tolerate, to bear.

Plonker is a very colloquial British-English word that means a stupid person. British English is rich in such words! Other examples are twit, wally, nitwit, twally, prat, pillock and burk (or burke or berk). None of them is really vulgar, but the safest in this regard is twit.

To moan means literally to make a vocal, but not verbal, noise, such as to indicate pain or illness. Colloquially, it also means to complain or grumble, typically about something that isn't very important.

Nine times out of ten literally means on ninety percent of occasions. In conversation, it just means almost always. We also use the conversational expression more often than not; for example, More often than not, I have to work at weekends.

Why do I bother (doing or to do something)? means why do I make the effort to do something? especially in a situation where the effort seems to be wasted.

We say that somebody doesn't bother to do something when they don't make an appropriate level of effort for the situation, perhaps because they're lazy or inconsiderate. For example, He didn't even bother to write a thank-you letter.

We say can't be bothered when to take a certain action requires too much effort, in the opinion of the person concerned. For example, I can't be bothered to go to the gym today, or I can't be bothered to help him with his project. He didn't help me with mine.

We say You know what they say when we want to quote a proverb or another popular saying.

You can lead a horse to water, but you can't make it drink is a proverb that means that it doesn't matter how easy you make it for someone to take a specific desirable action, you can't force them actually to carry out the action, even if it is in their interests.

To get cracking is an informal expression that means to begin to work enthusiastically on some task.

We say that time is flying to indicate that time passes quickly.

A lot to cover indicates a lot of material to deal with. The image comes from the expression that we typically use to indicate the distance travelled. For example, He covered the distance to the office in half the usual time.

Hang on is an informal expression that means wait. We also say hold on. There is no great difference in meaning.

To butt in means to interrupt. The image comes from the action of striking something using the head, such as a goat or a bull might do.

A heads-up is a notice or warning to people that they should be aware that something significant is going to happen. The image comes from the idea that busy people typically work with their heads down, focused on what they are doing. This expression indicates that they need to raise their heads to pay attention to what's happening around them.

We say that something slips our mind if we forget to do something that we should have done. The image is that something has slipped through our memories.

To have a memory like a sieve is an idiom that indicates that we have a poor memory. A sieve is a grid, usually of metal, that is used to filter out larger objects, such as lumps in flour, by letting the finer material slip through the grid.

We often use go on to mean yes, do what you have just suggested. For example, Would you like me to make a cup of tea? Oh, go on, then.

Go on can also have the meaning of continue. For example, We can't go on like this.

To run late means to be behind the expected schedule. For example, The train is running nine minutes late; in other words, the train is nine minutes later than the times in the timetable.

In British English, cheers has two main meanings. The original meaning is as a toast when having a drink in company. The newer meaning is thank you; in this sense, it's very informal.

Seeing that is an informal way of saying in view of the fact that, or simply as. It's not grammatically elegant, but it's accepted informal English.

To turn up is an informal way of saying to appear or to arrive. The shade of meaning is usually that there is something unexpected about the arrival; for example, I waited for ages, and she finally turned up an hour late (she was unexpectedly late); or, It was a formal party, but he turned up wearing jeans and a T-shirt (he was dressed in an unexpected way).

To stick something somewhere is a very colloquial way of saying put, in various senses. It has no connection with to stick in the context of using glue. For example, I wrote a cheque and stuck it in an envelope; or, Here, stick your name and address on this form.

A do in informal British English is a party.

A week on (for example) Friday means a week from the Friday of this week; in other words, not this Friday, but the Friday after that. You may also hear on Friday week, which has the same meaning.

A whip-round is a collection of money among a specified group of people on one occasion, especially for some good purpose, such as to help someone who has a specific need at the time or, as here, to buy a leaving present for a colleague.

We introduce a statement with needless to say when we feel that the statement is so obvious that it's not really necessary to say it.

To chip in means to contribute some money in the context of a collection among a larger group of people (i.e. a whip-round).

To talk someone into (doing something) means to persuade them to do something. The opposite is (not surprisingly) to talk someone out of (doing something).

To think something over can mean (depending on the context) to consider something (such as an offer or suggestion) very carefully, or (as here) to reconsider something.

The expression locking the stable door after the horse has bolted means taking action to avoid a bad situation that has already happened; in other words, it's too late to avoid the bad situation. To bolt comes from the world of horses and describes how horses may panic and run away. In the image, our horse has already run away, so it's too late to lock the door of the stable (a building where horses are kept).

To be fed up means to be in an unhappy, negative mood, especially one that has a specific cause, such as having too much work or having large bills to pay. We also say to be fed up of / with (something) when some bad situation has continued for too long; for example, I'm fed up of all this rain. When is the sun going to shine again? or, I'm fed up of my boss expecting me to fix all his mistakes.

To carry the can (for something) means to take the blame for something. For example, I'm fed up of having to carry the can for all your cock-ups.

A cock-up is a slightly vulgar expression that means a failure caused by human error.

A roll-out means a product launch, the introduction of a new product into the market. The image comes from a new model of machine, such as a car or an aeroplane, which is rolled out of the factory for the public to see for the first time.

To stab someone in the back means to pretend to be someone's friend while secretly acting against them in some way.

We say the chickens have come home to roost when we experience the negative results of some bad action or decision that was made earlier.

Informally, we can use next to with an adjective in the sense of almost. It has a more emphatic sound.

To take someone's place is a more conversational alternative to to replace someone.

For some strange reason, to know your onions means to have a good knowledge of your subject.

Cheesed off is a very colloquial British-English alternative to fed up. More vulgarly, we also say pissed off (in US English, just pissed, which in British English means drunk!).

To be in someone's shoes means to be in the same situation as that person.

To make a start is equivalent to to start in the sense of beginning a piece of work. The expression is used with no object; we can't say, for example, to make a start work or to make a start to do something. However, we can say to make a start on something; for example, Let's make a start on painting the kitchen.