Tips on how to take care of Red Eared Slider Turtle

My mom bought me A Red Eared Slider turtle,the thing is i don't even know how to take care of it all i do is just feed And Clean her water and her shell,
is there any pro turtle keeper out there please give me some tips on how to take care of them.

BTW How high the water is supposed to be in the aquarium.
What Am I going to do When my Turtle lays an egg??

Sorry for the questions I'm Just 14 and i'm new to this turtle thing

EDIT:i'm going to take some picture for you guys she's cute