Recently I purchased a good performance hybrid made by Diamondback and I noticed that the V brakes on the back wheel were rubbing against the wheel. So being a beginner and all I searched "how to adjust V brakes" on Youtube, in one video it said to make sure the wheel was in properly and the man used his quick release to make sure the wheel was installed right. I did this on my bike but I think I messed it up because the rear wheel doesn't look like it's spinning straight when I ride it. Also, I disabled the rear brakes and I can't get them back on because there's too much pressure on the cord. Can anybody help me?