How to do post pagination?

I’m trying to find out how to have “previous/next page” buttons on the bottom of a post
can’t seem to figure it out, I’ve tried plugins and they all don’t work because they require you to input code into various .php and .css files.
does anyone know how/have this done on their page?

this is what it currently looks like
example
“page: 1 2 3 4 5 6…”

I’m trying to make it so it looks like;
“Previous 1 2…5 6 Next”