The UK college apps system is called UCAS, short for the Universities and Colleges Admissions Service. Like the US, it is a website where you fill in everything and yeet it to the colleges at the end. Unlike the US, this is the only place you need to be stressing over your application on. There is no other place you can apply to college on (if you're going through the most conventional and common way, like everyone else. That includes every senior outside the UK who wants to go to college there) unless you have special circumstances. Say, if you're doing a foundation course rather than doing A-Levels. If you're unsure, you can search online because I'm not an expert on this front either.

Basically the technical parts of the UCAS application contains three parts (not including financial aid and scholarships). 

1. Your UCAS app ​​​​​​
- This is where you fill in all of your personal information. Stuff like where you are from, what school you did, what exams you did. It's a fairly simple form, so you can figure it out as you fill it in. If you need help, I'm sure your school will give it. There are probably Youtube guides that talk about this, so I won't be going too in-depth about this.
- You will also be filling in your college choices into this. Note that the UK only allows you to apply for five choices. A choice = course + university. 

2. Personal Statement (PS)
- The most crucial part of your application. It doesn't matter if you have an interview or not. This is the most important thing in the application. 
- The personal statement is basically a CV in essay form, where you talk about 1. why you want to do this subject 2. your achievements and 3. why the school should accept you. This is the part which everyone stresses over, because you got to grab the admissions tutor's attention in 4000 characters. That's about 500-ish words, and trust me, it's not that much. Anyone with a decent profile will definitely write over the word limit, and that's expected. What matters at the end is that you hone it to perfection before sending it to the universities. 
- Yes, you will be handing in one single PS to all five choices. This means that you got to show that you have an interest in all of your five choices in one document, which significantly narrows down your choice ranges. This also means that you have to tailor make this thing so that it can win all five universities over. 
- To those courses with interviews (I'll talk about this below), the PS is a ticket to your interview. If the adminissions tutor gets hooked enough with your PS, they will call you in for an interview, and if it's not interesting enough, they won't. It's as simple as that, so you definitely have to make sure you get it through 

(2.5 Interview + Admissions Test)
- This part is entirely up to the course you chose and the universities you're applying for. For example, all medical degree and law degree students have to do an admissions test (there are some law schools that doesn't require this, but most do). All Oxbridge candidates have to, as well. The Admissions Test is a way of testing your ability and you don't have to study for it, or rather, you can't. It asks you stuff based on your chosen course, and tests your base knowledge, or with humanities/social sciences subjects, your critical thinking and judgement skills. 
- I'm not sure which one goes first since the admissions test for my course luckily got cancelled this year. I think you do the admissions test after you hand in your PS, and the interview depends on your performance on the admissions test and your PS, so keep an eye out for that.
- For interviews, you have to do reading. Both on general principles in your course and what's going on around the world. So for example, if you're going for medicine, you have to know about the newest discoveries and diseases like COVID, stuff like that. I'll elaborate on interview tips later. 
- The interview is the part where you distinguish yourself apart from other candidates. So if you have an interview, you got to shine. You'll be counting on that interview to get your offer.
- To recap, PS -> Admissions Test -> Interview

3. Transcript 
- Basically a recommended letter from your teacher. I think in most schools you can choose your teacher, but in mine I don't. I get stuck with my tutor, a teacher who supervises our process, except she was new and she teaches math (note that I'm applying for social sciences). So good luck to me. 
- This is likely attached to your UCAS app before you whisk it off to the universities. If you can, try to find the teacher who knows you the most to write it. It'll be easier to coordinate and would make you shine more. 

What the school does for you
1. Predicted grades
- It gives you a set of predicted grades which you use to apply to your choices. There is a range of grades available in the course website, which is often the bare minimum. Basically, if that med degree requires AAA*, if you don't scrap that much in your predicted grades (this is an A Level example), you can't even apply to that degree. Period. 

2. Transcript
- Elaborated above. 

What happens after I get the offer? 

Offers typically come in February - March-ish. Sometimes January. I don't think anyone releases offers in December, because it's too close to the UCAS submission deadline. Anyways, once and if you get the offer, it will be a conditional offer. What you have to do to complete the offer, to make it into an unconditional offer is to achieve the expected grades in your A Levels or the college exams you'll be taking. 

Note that the grades you are expected to meet can sometimes be flexible, especially for Oxbridge. For example, if they expect 2As and 2A*s, I think they'll let you go if you only have 1A*. After you get an offer, of course. But don't expect such leniency from other universities, and study hard to fulfill that offer you got.

Once all of your offers are in (the universities will tell you whether you're rejected or accepted), you have to choose two courses by a deadline. One of them is a set choice, meaning that you've decided to go there if you fulfill their grades. Another is a back-up; if your A-Levels got crap you're going there. I'll elaborate on this more in the second page. 

You only get your results at Results Day, which is usually in mid-August. This year it's on 13th August, which is precisely two days from today. Yep. Totally not freaking out now. Anyways, once you get your results, I think UCAS will automatically update you and you'll know which university you'll be going to. If you can't fulfill all of your grades, you go to Clearing (more info on that later).