High School MATH summer camp preparation?

I’m interested in applying to a math summer camp this summer and notice that some of the applications require you to go through a set of math problems and write down your work while solving.

I am a junior, currently in AP Calculus BC, and school math is not a hard subject for me, but I am no where near able to solve most of the problems that I see in the practice sheets.

I was wondering how I could best prepare myself for these summer camps when the applications open up? Are applicants naturally able to solve all of these problems??

Thanks.

https://artofproblemsolving.com/
The Art of Problem Solving has an online school with classes that broaden your math knowledge.