How to code twin background images

Hello,

I am completely new to this, so please bear with me.

We have bought a template for our business, which does not have native background support. However, i would like to have an image on the top right and one on the bottom left of the page.
I checked other topics and followed a couple tutorials on how to do it, but i can not get it to work at all. Right now i’m baffled between different <div>, <p style > and body { … commands and have no idea which to use and where to actually put it.

My images are in the theme/assets/img/backgrounds folder, and i would like to know where i should put the code and which i should use.

Thank you.