I didn't do anything too fancy : just the 3 muscles I know and I can see (sometimes...) on my own arms
the biceps, triceps, and... the other on the side I don't remember the name...
You take a little ball of paste, you pose it on the place you want to reproduce the volume (a muscle for example), then you strech the paste ball to stick the rest of the figure, and fill it in the main profile. Then, with tools you try to make it look like what you want. In that case, big Hulk muscles
I'll make the face, now.
DImitri