pathway to username;password area

Hey all, I need some quick help!

I FINALLY set up the site, and someone refferd me to this program for my member login area, they said i could even try it out for a month. Well because I am not very php literate I had someone apply it to the site for me. Everything has worked good since, very easy to use.
Today I got approved for my merchant account and they called to ask where the pathway to the place where username and password are stored. Again, i am not very php literate so I have to get back to him. Any help on the matter would be greatly appreciated!

Thanks in advance
-Kevin

does it matter at all if I am using a mySQL with amember? does that change anything? the customer rep at ccbill seemed to be getting a little impaceient with me on the phone and just told him i'd call him back when i knew for sure

Thanks alex, but now I have run into yet another problem.. CCBill is trying to tell me there is an internal error when using mySQL database. So they told me that the clients of theirs that use amember generally use the postback system when i have never heard of... He explained it to me and said that when someone signs up it posts back to a url. He also said I would need a script to do so. Would anyone have such a script?

Thanks again
-Kevin