Unfortunately oauth cannot be compressed into a cheat sheet.
But yeah, oauth is absolutely something you forget right after using it and have to bootstrap every time you touch it.
What's so hard about a specific authentication flow?
You have a user, a client app, a resource service, and an authorization service. You have a sequence of requests that send data back and forth. The end result is a token that client apps can send to a resource service. What bit requires volumes to understand?
Take a minute to check RFC6749. All authorization flows in there require between 2 to 6 pages to fully define. Is this too much info to parse?