Ideally you should not be able to see where the 2 threads connect, that should be in the sandwich. If the bobbin thread is just laying along the back then you need to adjust your tension. My Bernina likes the top tension at about 5-1/2 to 6 for FMQing and I adjust my bobbin tension. If your bobbin thread is just laying on the back then you need to either tighten your top tension or loosen your bobbin tension. Take a picture or make a note of your bobbin screw before adjusting it. Turn it in tiny bits until you get a balanced stitch and then turn it back for regular sewing.