The most important advice anyone can give you is to begin. Where, how hard, how fast, which exercise...those little details are not anywhere near as important as getting off the couch and getting your CrossFit on. But, just so you have a place to start...do the WOD. But just so you have a more complete recipe do this:
your home page and go there often. Subscribe to the CF Journal. Read Foundations and Getting Started. Start building your home gym. Get your diet in order and start Zoning your way to a proper performance enhancing diet. Go to the FAQ's and many of your questions will be answered. Read up on what a certification seminar is like and you'll find that in the FAQ's. Plan on attending a cert some time in the future.
Learn the CF warmup and the Burgener warm up and work your way up to being able to do them. Yes, the warmup is difficult...at least the CF one is, and you will have accomplished something just to be able to get through that as prescribed.
Do the WOD. You will have to scale the workouts to what equipment you have available to get into a three days on one day off schedule and stick to it as if your future fitness depended on it.
Oh yeah, it does.
Your email makes it clear that the roadmap is sitting in front of you and you have a pretty good idea what to do. You even have a CF facility to go to...so there is nothing in your way.
Get started. Jump in with both feet. You can't cross a chasm in two small leaps. You can't begin an exercise program of any kind without actually begining. Stop reading and start training.
Welcome aboard and keep us posted as to your progress. Good luck.