How do I change the tension? I'm not really that technical about sewing machines, but on this one there's the knob to change the stitch pattern and then a lever for reverse and that's about it for knobs.
It's the same bobbin I've used, but I may have put the bobbin in the metal part wrong.
I don't have your brand of machine, but there should be an adjustment knob. Mine is on the same end of the machine above the needle. (as opposed to the other end with the hand crank and power cord). This probably isn't helpful but its all i've got