While I don't believe M20 has details on _running_ an awakening (since it assumes that starting characters have been mages for a while), Initiates of the Art is a whole book dedicated to the newly awakened.

That said, given how personal an individual's awakening is (and practically no two are alike), I would run it as a session zero with the player describing the events that lead up to his/her awakening (i.e. little to no dice rolling and let the player make all of the important decisions, but the GM prompts important questions / conflicts for the player to decide).