Welcome to Tug.
There are numerous threads here on how to sell your timeshare. Search the forums, and read the "sticky" threads at the top of each forum main page. But before you do, be prepared for some reality checks: Chances are very good that if you paid a large amount of money to buy it, you're very unlikely to get that when you sell. Most timeshares are selling for pennies on the dollar, and some can't be given away.
Dave