hei i am starting high school and i have been playing the gitar for a while and i know a few people that can play drums and bass, so how do i start a band?

Ask them to sertai you.

First see if anda have permission from your parents. Then find a place anda can practice together. It can be anywhere, like Parks, garaj of any member, atau a coffee shop. After anda have done these things decide a cool name for your band depending upon what kind of band anda are making, and ensure that it isn't same as any other band. anda can make a Rock and Roll, Emo, Punk, atau any other genre anda like. Then after anda have decided the name start practicing. First as beginners anda can sing covers of your fav songs and later anda can write songs on your own. To popularise your band anda make band posters and paste it on public places so that people would come to know about it. anda can organise small shows at occasions like your friend's birthday atau some get-together parties.
So, get going and rock it!! I think this will help you. :)