I learned it by having problems to solve and reading the Help files. You can
learn just about everything in the help files. I also had the benefit of an
office-mate who was already pretty proficient. At first, when I was starting
out, he gave me a few programs to work on and then he would help me only when
I just couldn't get out of a jam. There were times of frustration with this
method, but it worked pretty well. You could use these forums as that
"person" to help you get out of the occasional jam.