[Zope] LoginManager - how does it work?

I've managed to get loginManager to install, but I am very confused as to what to do with it. I've read the how-tos on zope.org, and the documentation of LoginManager itself... But I still don't understand what is supposed to happen. A User Source is a location to find users, Say, my SQL database, right? How do I tell it to use the SQL methods I have for retrieveing passwords? The how-tos say to create dtml-methods called "userAuthenticate" "userExists" and "userRoles". Where do these go? Can anyone help me see the light on this? Thank you