Use a couple of yards of cheap fabric (Walmart $2 clearance) and a backing of another cheap fabric. You'll need to cut the batting the same size as the backing, but top should be at least 3" smaller on all sides. This will give you something to practice on. I suggest you start without using the stitch regulator and practice free-motion. The stitch regulator is really great when you're doing stitch-in-the-ditch, pantos or intricate work. You don't have to be worried about mistakes on this practice piece. You will probably need to work on your tension. Always check the bottom of your quilt frequently. READ YOUR MANUAL!! This will tell you how to thread the machine, load the quilt, correct tension and other problems. When I finished my practice quilts, I would bind them and use them as lap quilts or in the back seat of the car when I haul food or take the dog to the vet, etc.
Don't get discouraged if it seems hard at first, it gets easier. Just relax and have fun...you will fall in love with it!