Well, you are in the right place..
Start by reading here in the beginner's section.
Honestly, it doesn't sound to bad if most of your debts are that old.
You've gotten your CRs and really, that's the first step.
The next thing you should do is update any/all personal information. Get as many addys, name, ss# variations deleted. Delete phone #'s, employment history.........basically as much as possible. (you can do it over the phone or online and it will go a little quicker - but anything else as far as disputes should be done by mail)
Go here and opt out:
www.optoutprescreen.com
It will keep the CRAs from sharing your information with 3rd parties and keep you a little more hidden while you are fixing your credit.
While you are waiting for the opt out and personal info to get update.........triage your reports, go through them and see what's reporting incorrectly. Anything over 7 years old, dispute as obsolete. After that start with the oldest debts.
That will kinda get you started. Then stick around and read here. There's a lot of info. If you have questions, just feel free to ask and we will try to help point you in the right direction.