Hi Julius, as Erik, has pointed out, there are lots of mocha tutorials out there. I suggest that you start off by visiting
http://www.imagineersystems.com/support/training . Start off with Steve Wright's tutorials. They will give you a good insight into how to work with mochaAE/mochaPro.
One advantage mochaAE/mochaPro has over boujou is that mochaAE/mochaPro will allow you to apply splines onto the guy walking in the scene. You can link the splines to tracks that you have conceived within mocha, and then export these splines as a mochaShape Layer or as AE masks.
HTH
RoRK
Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer
