As for the original question - "what happens after the FAM?":
After the FAM, assuming you are successful, you will be invited to attend Safe Person Training and Assessment. Basically all the training you need (safeguarding etc) to work with you people. You will also require an Enhanced DBS check, among other things. Once you have done this, you are a "safe person" and can attend a unit. You will then carry out the Basic Instructor Training.