Some years of experience in Linux should be enough to help you edit the files you need
Don't forget to be root when editing /etc/fstab!
When you're in /etc you can choose an editor if you want a editor that beeps every second type:
If you want an easier version that beeps every five seconds type:
If you want another much easier version type:
And finally if you want an advanced, not too difficult, good looking editor type:
Now the editing! I can tell you a lot about all the editors, but to make it easy, I'll only explain emacs and vim.
In vim, at once you have started it, type i and you can start editing your file. If your backspace key don't work, use the arrow keys to the beginning of the word/line to remove and press your delete key. When done editing, press esc and type : and you'll see a : on the last line, then type w and your file is saved. Then type :q to exit.
In emacs you can begin editing without pressing any keys. When you're done press F10, then f and then s. Your file is saved. To exit type Alt+X+C and you're done!