Sandisw advice is excellent. Also, start reading the threads on both this board and also the the
DVC planning board. That is how I learned about DVC prior to my trip when I took the tour and purchased. I probably spent 3-4 months researching before my trip.
Also, don't be afraid to post questions, that is a great way to learn.
Once you have done some research, please keep in mind, that you can eith buy directly from Disney or through resale. The resale prices tend to be lower but it will take longer and you will have to go through the ROFR process.
(ROFR is Right of First Refusal. Basically Disney has the right to buy any resale contract for the price agreed to by the seller & buyer. If Disney exercises ROFR, then they buy the contract for the agree upon price and the buyer has to find another contract.)
check out the ROFR thread
ROFR thread part 3 to get an idea of the resale prices.