There are many ways to go about creating your own font. This is a simplified approach. You can find many 'free' tools online for converting handwritten type into fonts as well but they don't always work that well.
In Font Book, on the far left, there is a "Collection" column that contains three main collections called All Fonts, User and Computer.
The lab build resets fonts after every user session (the time from when you log in to when you log off). When you log off of a lab computer, it resets any fonts you may have loaded to Font Book during that session.
On public lab computers in the Applications folder, you will see a folder called Adobe Font Folio. This is a collection of particularly lovely Fonts created by Adobe and provided by MCAD for student usage as part of you