How to build a booty?

So my ultimate goal for my body is to get a bigger butt and some how wider hips. Everything I’ve read has been completely different and I have no clue what to believe and what not to believe.

I’m pretty sure I have a mesomorph body type if that helps and I’m 15.

I just wanted to know if it is possible for this to happen to my body and what I should do to achieve it.

Here are some photos and don’t mind my stretch marks and very messy room...

Please comment!!