So i have to compare them
Come on this is something that is not even close to be perfected; Way to big a question and impossible to answer completely.
I would suggest using the
Kinect SDK[
^] to work with skeletons and then compare the movement of the skeleton of the user with expected movement of the base skeleton.
This however is not easy it would be worth a PhD thesis, and since you asked this question I'm pretty sure you should forget about it and move on, as it's beyond you at the moment.
This might sound harsh, but you don't learn anything by taking on a project you're doomed to fail, you'll only waste your time and knock down your confidence more or less.