First of all you must have an etherwallet. To convert your token into ether you must have an eth first , this will be your gas and fee for the transaction of your tokens. I recommend that you use etherdelta because it has so many compatible and available tokens. Once you have an eth in your etherwallet, you will have to deposit your token in the etherdelta to be able to sell it and be converted into ethereum. When you are finish selling your tokens and converted you can now withdraw your eth into your etherwallet. Its that simple.