Need Help/Advice for ACT Test

Hi guys I’m a junior in high school. So far, I haven’t taken the SAT/ACT (or any of the practice tests). My counselor said I need to get serious about this and should take the next ACT, and then take it again next year to improve the score that I get.
My questions:
(1) When’s the next ACT? I looked it up, and it said April something, but does that apply to all schools?
(2) What is the ACT? Like general information needed. Give me a website for info such as what is gonna be on it, how it works, etc.
(3) How do I prepare for it? (Any ACT practice tests, or overall practice material)

Thanks guys.

EDIT: Also, what is a good score for the ACT (by good I mean competitive)

The ACT has specified dates that apply to all testing centers in the US, so the next ACT date will be the one you saw online.

The ACT is a standardized test used in college admissions, the website is easy to find, just type ACT into google and the official one should pop up first. Usually students tend to be better at either the ACT or SAT depending on their natural strengths or ways of thinking, so I recommend taking both at some point to compare. Math, Reading, Language, Science, and Writing (optional) are the ACT sections.

Official ACT practice books and material are sol on their website, also, they have a youtube partnership with Kaplan where they post free ACT informational and prep courses (these helped me).

The national average score for the ACT is 20.8, so anything above this is a fine score. Depending on what colleges you are looking into, you will want to aim for a higher score. Top schools (Ivies and the like) usually look for a score of 31-36 (aim for a 34 or above if you want to be a very solid candidate), competitive institutions usually recommend 29-32, good state schools around 25-30, less competitive schools maybe 20-24.