Probably the best bet is to buy or check out at the library some body building
books.  They would explain how to build up each muscle group, but that
way you could see what that muscle group looks like and the proper name
for it.  It would also act as a guide so that you could shape your character
to look like one of the models in the book.  Then just start turning the dials
until your character's muscle looks like the one in the book.