You should give https://www.wagnerheim.com a try (by Paul Heise). It's very comprehensive, though keep in mind that it's one man's interpretation. Indeed, it's impossible to just "set out" all the themes and leitmotifs of The Ring, because there isn't any agreement on what they are.   Here's a relevant excerpt from The Ring of Truth, by the late Roger Scruton:     In terms of a step-by-step guide of The Ring, though, I don't think there's anything better than Paul Heis