The process is pretty simple, or it can be as complicated as you want to make it.
There are a number of venues for renting points -- eBay, Redweek, the DISboards
DVC Rent/Trade Board, etc. For someone new to renting, the DISboards is probably the easiest.
The first step is to read the R/T FAQ and the sticky entitled "A Word to the Wise."
Then post a listing on the R/T board offering however many points you want to rent. Giving the use year is helpful to DVCers who understand use year, but non-DVCers will want to know where you can make ressies and when. (e.g. can make SSR 11 months ahead, any other resort 7 months ahead).
The terms of the rental are strictly between you and whoever you rent to. I would have a clear idea of what you think is fair, and what is not. Obviously, you will want to be well aware of your banking deadlines, end of use year, 31 day cancellation deadline, etc. etc. just like you would if you were using the points yourself.
Many DVCers use formal contracts; many do not. (If you do a search on this forum for "rental contract," you'll probably find examples) Whether you use a contract or not, you need to have a clear understanding with your renter about the price, dates when deposits and final payments are due, and what the procedure is going to be if they have a change in plans.
As much as you want to help people have a great vacation, you have to take a businesslike approach to changes. People whose plans change are much better off paying cash through CRO, because they can usually cancel without penalty. Your situation is very different.
You need to have your own mind straight that changes in THEIR plans are THEIR problem. You can certainly
try to help them with unexpected plan changes, but your options may be very limited in a variety of situations.
Changes in plans are what
trip insurance is for, and they CAN get trip insurance to cover a DVC stay. There are a number of good trip insurance companies -- tell them to Google "trip cancellation insurance." If they're using trip insurance, an agreement that clearly states the reservation is non-refundable is very much in
their best interests.
If you get a renter who is bouncing all over the place, or wants a better price, or claims a personal hardship, or has a lot of demands, many will advise you to drop them and just move on. There are plenty of people to rent to, and there is no need to do business with problematic people.
When you get agreement on dates and terms, you just call MS and make the reservation in their name. When you get the confirmation, many DVCers send them a copy, as well as your contact info and MS's phone so they can independently verify the reservation. They CAN'T change anything; the reservation remains completely under your control. So...if they don't pay you, you just cancel the ressie and get your points back.