When quilting straight lines, you can use your walking foot but unless you go in only one direction, you will need to turn your quilt. Turning a quilt to do the stitching is hard.
You can FMQ straight lines by having a ruler foot and a thick ruler. This allows you to keep the quilt in the same position but quilt in any direction you want sewing along the ruler. ( Just like the long armers do but on your sewing machine) Since the feed dogs are down and you are controlling the stitch length yourself, I sometimes get an oops.