Did you check out the Tutorials section?
You can also have a look at the Rhino blog
it's got plenty of links to free tutorials.
Good luck with your thesis!

http://www.grasshopper3d.com/video/4-crv-srf

hi angela ,apart from the tutorials section on this website which include few good referrence books and video tutorials , you could also check out digitaltoolbox.info , this website has good amount of tutorials both for rhino as well as grasshopper in three different levels.