Depends if she is messaging you back. If she is, and seems responsive, I'd say have a good convo, then wait a few days, make her eager to hear from you. And if you haven't already, ask for her number! That way you know if you are wasting your time or not.
I don"t have a fb account but I had it.I never did.But for you maybe 2-3 times a week
Never it'll seem as you are stalking her
Meet her one day and just simply ask her out
None. Unless he does that. A lot
a couple of times if she seems interested
If she's not replying then stop doing it..
Once every two weeks. You don't want to seem creepy
once or twice so you know she got it then no more and get her number
Once and get her number through there..I know many people who don't spend all that much time on Facebook so don't do it a lot.