Appointments+ facebook login/remember credentials

I was wondering how it is possible for this plugin to "remember" a returning customer so that they do not have to fill their information out every time they want to make an appointment. also, i see that the plugin page boasts the ability to login with facebook to make reservations (awesome) but i do not see how to accomplish this.

I also need to know how this integrates with the membership plugin. that plugin is so entirely complex that i just got lost in it for about 2 hours and still dont have anything working with it.

in short, all i want to be able to do is have someone come to my site, create an account that can be used to book appointments and nothing else. the next time they come to the site, it will remember them, or they can just log back in and all of their details will be remembered. or the facebook thing would be REALLY nice.

please let me know how to get something like this going. thanks!