Do step-by-step directions exist?

Can someone point me to step-by-step directions if they exist. I can make changes to the code, I just can’t read it and don’t know where to make the alterations.

I’m specifically looking to have my portfolio pages loop end to end.
and possible change the background color of the buttons and/or move them.

https://ww.wp.xz.cn/plugins/next-page-not-next-post/