How does Warrens Abstract Machine work?

I’ve recently learned about prolog and Logic programming which I find pretty cool, but the compiler is currently like magic to me and I want to know how they work.

After a little bit of research I discovered that logical compilers are based on Warrens Abstract Machine (WAM). I’ve tried to find some information on WAM, but the Wikipedia page only describes what it is and not how it works and the book Warrens Abstract Machine: A Tutorial Reconstruction doesn’t read very well for me.

Could I please have basic explanation of how WAM works?

Thank you.