First things first...breathe...
I totally felt the same way as you when I first started this venture. I had no idea where to start. Then I found BDW and all my trouble's seem to have disappeared!
Okay, you have already picked your destination and resort...believe me, THAT is half the battle. I had a hard time trying to decide...there are so many of them out there.
Next, I would try to narrow in on a date that you would like to have your wedding. When that is finished, talk to a TA and let them know the dates that you plan on getting married and then pick a week for travel and get some quotes for group travel. If you are planning your wedding far in advance (like more than a year or so), don't get discouraged if the prices seem ridiculous...it only means that the published prices for the resorts aren't out yet. I FREAKED out at first because I couldn't get any quotes until mid-December 2008 for a planned November 2009 wedding...which is why I am getting married the last week of October...they were already published before December...LOL! I can be a little OCD at times! My FI calls it impatience. LOL!
Once you finally decide around what dates you are interested in, get in contact with a wedding coordinator at PPR (BEAUTIFUL resort BTW) and secure a wedding date...after that, get your group travel in place.
I hope that helped some. Good luck with the planning and I promise you that you will enjoy every moment of it...even the frustrating times!