Knob confusion on Retro Singer Sewing Machine?

My aunt recently gave me a sewing machine that worked perfectly (Fashion Mate 248) and I'm attempting to use elastic thread. My problem is that someone has messed up the dials and I dont kno what to set them on everything I have tried has caused the top thread to knot around the bobbin under the plate, or the thread to loop up underneath the fabric . there are three dials one on the top front of the machine (I dont kno what its for) then two on the side, one controls the tension, and one bigger one controls the stitch length I think. I've always been a hand sewer and am new to all the knobs thanks ya'll!