If you have Release Candidate 2 or 3 installed for your Cockpit, you should be good to go as the IMU is already enabled in those versions.
SSH stands for Secure Shell. It's basically a way of logging into another computer(BeagleBone Black in this case)...from another computer (your laptop). With the inclusion of the Cloud9 IDE, SSH is kinda irrelevant because you can just make all the changes in the IDE without having to worry about SSHing and learning how to navigate via command prompts.
I was having a hard time understanding all the programming too, so I picked up the Programming book by Simon Monk and I have a pretty good understanding now. Programming BeagleBone Black