Please! Teach me!

How do I make my own story background?
HELP ):

I feel like I'm always asking for help, but at least I'm attempting to learn right!?
I just need someone to like explain it to me.
I've tried to make a new one and I can't see to get it right! it's starting to annoy me, but I want to be able to make my own backgrounds. I feel like such a lame that I can't.
So somebody please! Teach me! ): Pretty pretty pretty pretty pretty PLEASE!
Or if there's a button or something that says "how to create story background" could you tell me where that is? I am on my hands and knees begging YOU! Yes YOU! /: