No uniform required! Bring a few pencils, an approved graphics calculator, food, water. That’s really all you need.
I’d also recommend bringing some alternative clothes (I’m very temperature sensitive during exams, so maybe that’s just me - I wanted to make sure I could change quickly to stay at the right temperature if I needed to).
A ruler can be helpful for the essay and reading/writing sections of the exam, too.

We’re allowed to eat during the exam?!

How do I check if my calculator is approved? Thanks!

You get breaks between each section to use the bathroom and have something to eat, but only about 5 minutes at a time.

As for the calculators (Definitely make sure yours is a graphics calculator, as this can get you 200+ free points in the calculator maths section):

Awesome advice! One last thing - the currency when paying on collegeboard is USD right? And around $100 right? And it’s the only place where we can register?

Also do you think it’s worth paying extra for the question and answer booklet I think it’s $18

I just don’t want to get taken advantage of or anything since I haven’t much clue haha

Thank you!!!

Yep, that’s right. I wouldn’t worry about any of the extras personally - there are free practice tests online w/ answers and explanations, so it’d just be like paying for one extra of those. If you’re looking for further support on top of what can be found for free online, definitely let us know!