Versed means skilled in a subject through long practice. You know it because you have done it for years.
It only ever appears with in, and almost always with well in front, so well versed in the rules is the standard shape of the phrase. It suggests thorough familiarity rather than formal qualification, which is why it suits practical knowledge. The word comes from a Latin root about turning over, in the sense of turning something over often. There is no verb to verse in this meaning, though American slang has invented one for competing against.
1adjectiveversedExperienced and knowledgeable in a subject.
“She is well versed in employment law.”
Also accepted in games: well versed, proficient