This should answer most of your questions:
On the individual items in the schedule, you can RSVP to each individually. Make sure to pay attention to the times, as some of the courses occur at the same time! Don't wanna double book yourself.
Edits: Perhaps you wanted some clarification on the registration they keep mentioning:
1. Go to: THWACKcamp 2015
On this page you'll see it say "Register for thwackCamp 2015 by clicking on the "Register Now" link at the top of your page. After you register, please RSVP for individual sessions below."
3. RSVP for the courses you'd like to attend!