Mark the center of the backing on the wrong side at the top, bottom, and side edges. On a smooth, flat surface a little larger than the quilt, place backing right side down. Smooth any wrinkles until the backing is flat; use masking tape to hold it taut and in place.
Unfold batting and lay over backing. Smooth wrinkles, keeping the backing wrinkle free.
Position quilt top on backing and batting, keeping all layers wrinkle free. Match centers of quilt top with backing. Use straight pins to keep layers from shifting while basting.