I'm interested in booking a provider who is asking for a referral. I'm new to this, and haven't booked before. What should I do about providing a referral? Is this some sort of personal reference, or someone with whom I've had a prior experience with? Either way, this seems tricky.

name of a provider you have seen before.  If you have not seen any, consider joining one or more of the verification sites, Date-Check, Preferred411, or RoomService2000.  P411 does allow providers to indicate if they are newbie friendly on their profile.  Also, Gina and her staff will work with you verify you.  It's better to give up some personal info the these sites than a bunch of providers.

So if I sign up for P411 and pay the membership fee, should that make me good to go? Or is there something else I have to do?

..such as myself, even if verified through P411, Date-Check, etc, will still ask for you to forward the completed appointment form from their website.  Verification sites are wonderful, but many of us do not use them as a sole means of verification.

As a newbie you may still have to provide her with more screening info to feel safe with you, but as you get a few OKs things get a whole lot easier. Some ladies still require personal information from you but many will except your multiple P411 OKs  as proof that you are a safe guy, if not it's up to you to decide if you're comfortable giving what she wants or move on to someone who will except what you are willing to give. Good luck, have fun and know that it does get easier.

but it will help you out.