Hi-good on you for giving it a go! You have described "basting the quilt sandwich" correctly, you want your pins to be about 4 inches apart (no steadfast rule here), and start pinning from the CENTER of your quilt, working out toward the boarders. If you are stitching straight, or "in the ditch" (stitching in or just next to the seam lines where your patches are sewn together:, start with a few stitches VERY close together, practically on top of each other, to lock them where you begin. Same if you need to end your row of stitching, make your last few stitches VERY close together or on top of each other to lock. You can sew over a bit of stitching you already have done if you need to to take you to another direction for quilting on your top. Walking feet aren't meant to sew backwards, but a few very close stitches are fine. You might want to take a few scraps from your quilt, "sandwich" them together and practice first. Good Luck!