Alright, glad I could help, but there's still one other thing left to do.
That change will only stay until you log out of that shell. In fact, it wouldn't be present if you switched to another shell right now. So, we need to make it permanent. You'll need to modify one of two files.
If you are the only user of the system, open ~/.bash_profile in a text editor
If you're not the only person using the system, open /etc/profile in a text editor (you'll have to be root to modify the file in this case)
Look for a line similar to the one I told you to type. If you find one, just tack on the :/usr/local/bin:/opt/gnome/bin to the end. If you don't find a similar line, scroll to the bottom of the file and add this:
Save, exit, and then the change will be automatic next time you log in.
As for an intro to linux in general, I've heard lots of people like the Rute User's Tutorial. You can find a copy of it here:
It looks like it covers just about everything. Otherwise, a Linux admin book or something similar at the bookstore can get you going. O'Reilly books tend to be good.