Can anyone please direct me into a better understanding of basic UNIX tasks?

Currently, I'm running AIX, trying to install a few apps, and getting the "file system full" message. I guess I'm supposed to allocate more space, (as I have a 36GB HD, and I've only installed the OS) but I don't know what I'm doing.

This is my CAD workstation, but I'll be using it as an entry level server later on, and I want to start learning more.

Thank you.