1.you go to " market "
2.then you click on the item in question
3.then above the sell icon we have 2 box`s these are for selling , the 2 above but are for buying
4.now in the top box you type in the amount you want to sell , the bottom box will show you how much it is worth on the market at the " price " value you have it on
5. click sell and wait for somebody to buy it :)