Please help me publish my game

So I made a game and now I want to publish it.
I watched this video but the finished apk is not my game ... why is there no easy tutorial or something like that?

EDIT: Also I did this, but when I moved the .apk to my phone and installed it, it always crashes on launch. I don't know why everyone but me seems to know how to do this

 

Do you even need android studio or can you just upload an apk created by unity?
I'm really confused right now and I searched the whole world wide web but found nothing ...

I thought making the games is hard but why does it have to be so confusing to just get it into the play store?

EDIT: Never mind. You don't have to use android studio ... no idea why I thought that you need it ...