Where to start is to either return the cheap flash or discard it and buy the correct one. I can't tell you how many times I see folks buy something to just get by or I don't want to spend too much money. It always winds up costing more and adds to frustration. The T3i is fine but you need to get compatible substantially equal gear to enhance its ability. I would suggest you buy a flash that will also be compatible with a newer model Canon camera. Again buy wise at the start because it is always cheaper in the long run.