Ok so have you ever sewn something then when you finished you see a big heaping mess of thread on the underside where you started? Well this is because the bobbin hadn't been threaded all the way correctly. In order to do so first you're going to need to put it in the machine the correct way leaving it with a couple of inches of extra. This is important. Not all machines are alike so I don't really know how yours needs to be threaded!