Getting a Facebook App ID number

Hiya. I'm in the process of trying to get a Facebook App ID number (which is required to give my clients the option to log in through Facebook when they pay for items on my website). When I clicked on the link provided in the pay per view settings file, the link was broken. I've since found the Facebook developer page on my own (, but they offer multiple apps, and it's unclear exactly which one I need. One of the apps is called 'Login,' and I'm assuming this is the one I need, but would like some confirmation of this. Thanks for your time.