Scoutmasters and Assistants must complete Parts A & B & C and the Outdoor Leader Skills weekend in order to earn the "Trained" emblem.
Parts A and B is the classroom training piece. By registering for Part A you are also registered for Part B. The registration fee of $5 covers both Part A and B.
Part C is the patrol meeting in preparation for the Outdoor Leader Skills weekend. You must register for the Outdoor Leader Skills weekend separately from Part A.