Best go about using Redbean? The project is well documented: https://redbean.dev/

Just go through it, it answers all questions you may come up with IMO.

Or you mean about embedding Lua? The official docs are great too: https://www.lua.org/pil/24.html

If you prefer a tutorial, there's plenty as Lua has been around for a long time. Search on Youtube for example and there's lots of videos.

The top hit on DDG for me was https://lucasklassmann.com/blog/2019-02-02-embedding-lua-in-... which seems pretty straightforward to follow.