How do i begin paying on these old accounts?

On your credit report it should say who you owe the money to. Just do some research on the company and call them. Once you call them they will ask you for all of your information like bank account number to pull the money from your accounts to pay it back. If these reports have been on your credit long then most likely it will be a debt collector that your calling. Hope this helps. 

www.freecreditreport.com 

Determine if the accounts you owe on are now collection accounts.

Contact collections company and request an amount you can settle on. 

(If you owe 500, and call the collection company, they will more than likely offer to settle for half the amount owed, depending on how long they've had the account) They sometimes will only settle for such amounts if you are able to pay the settlement amount in full. So maybe call and see what they can offer, and call back when you have that amount available.) 

This way, you pay less than you owe, and they will report the account as settled, instead of an open collections account.