I use the CDE to bring up a terminal window so I have access to the command line
As to books, there's a couple of threads around here but I used Essential System Administration to initially learn how to use the system. Mind you I've been using computers for a long time and seem to have an affinity to them.
Others suggest the Unix System Administration Handbook. I think there's some big "them vs us" camp on this. I have both and the Essential System Administration book seemed to work best for me.
Good luck and welcome.
Carl