It means that the quilt top is not attached to the poles (rollers) on the frame. It lays over the batting, which lays over the backing which has been previously pinned or zipped to the takeup roller and the bottom roller. After the backing, batting and top are on the frame, the quilt top is basted or stitched to the batting and the backing across the top and on each side of the top. Then when the quilting for that section is completed, it is rolled up on the takeup roller so that the next section can be quilted.