what the heck is instagram?!

How do you even post cool pictures on Instagram?! I want to look fun and quirky and interesting but I don't know what to post!! As of right now, I post exactly 3 posts (at the same time) every 2 months, each full of a couple of pictures of me, some online-found ones, of scenery etc. Basically anything I find cool. I even try to keep an aesthetic going! Still I don't feel cool enough!! Ugh!!