Up to this very moment, I am still trying to figure out how to use a DEX. I think I prefer CEX. The more liquidity and more user friendly interface of CEX makes me not want to venture into using a DEX. I tried one with forkdelta but I never succeeded I just gave up.
Try EtherDelta with their userguides on Reddit. Endeavor to use MetaMask which makes it so easy and smooth.