http://tesivpositive.animolious.com/ (Tomlong's site) is what you might want to start out by going through. Not all of it will be relevant to you, but a lot of it will be.
I recommend trying BAIN for installation/configuration/uninstallation of mods. It's better, in the long run, and will most likely save you heaps of stress/time/other. Plus, it's the way more and more mod users, and mods, are going. Still, you do have a choice: OBMM or BAIN. Mind you, both is another way to go...
Check http://tesnexus.com/downloads/file.php?id=35230 out too, for getting used to Wrye Bash's ins and outs, including BAIN, to some extent.
You can either go for OOO (a good option, and not too taxing for older PCs), OOO+MMM, or FCOM. Well, there are other options too, but going by what you've posted - they're the best ones.
I would probably try a pure OOO install, first. And yes, with a new character. Definitely.
If you get used to that - including the install/config - then maybe "upgrade" to either OOO+MMM (a bit easier) or FCOM (the "deluxe" version, so to speak).
If you read the readme files with any given mods, read the OP of the relevant release thread for each in the mods forum nearby, and follow those instructinos to the letter, you can't go too far wrong. Also, people will be more willing to help, happily, if you still need to post, asking questions in the correct mod thread(s). Nothing wrong with doing that - but it's certainly better to do everything you can, and at least
try to go about it the right way, *before* asking.
But generally, you'll find - especially if you do that - people in the mods forum are very helpful.
Speaking of which, hope that helps!