How do you learn what's important and where it is located? I know that
you can do google searches after you have a problem, and ubuntu forums
can provide advice for specific questions, but where can you go for a
good general education? I feel so frustrated blindly following
instructions, such as "type: sudo dpkg-reconfigure xserver-xorg -plow"
and no explanation about what I'm being told to do or why.

It's great having the experts to help me out of trouble, but how can I
get the education to become an expert myself?