As far as the actual DVC-RCI exchange process, there are two options, both of which involve a call to Member Services.
As Dean mentioned, you can do a search without depositing points. If you find an exchange you want, you deposit your points and pay the $95 exchange fee, and MS books the exchange for you.
If you don't find what you want, you have the option of doing an "ongoing search." You deposit the points and pay the $95 fee -- and that deposit is irreversible. I believe your points are available for use for two years from the date of your deposit. If you do NOT get an exhcnage with those points within the time period, you lose them.
The ongoing search is set up using the resort(s) you specified and the timeframe(s) you specified. If availability pops up that matches, RCI automatically books it for you. MOST exchange inventory is gotten by "ongoing searches."
I'm not an expert on RCI exchanges, but two things you should be very clear on are how long your points remain valid in RCI, and RCI's policies in the event you arrange an exchange and then have to cancel.