[Lizard]

The stuff you're doing is a little advanced, but Manas has done a pretty good job of going step-by-step. You sound like the careful sort (having read through everything before diving in) so it ought to be manageable. It wouldn't hurt to make sure you have a good backup of your Mac (Time Machine should suffice) before diving in.

sudo means something like "do this as the super user" where this is whatever command follows it.

There's some additional discussion of that particular step in the comments (particularly comment 31, but also a couple before that).