to join the yarn, position the two panels side-by-side with RS facing. Bring your tapestry needle through the front of the first st on one side, then insert through the back of the corresponding st on the other panel. Bring the needle through the back of the original st on the first side and finally take it through the front of the second side so you have a figure-of-eight. Pull tight to secure.
insert the needle under the horizontal bar between the edge stitch and the second stitch.
do the same on the other side and continue to work up the edge, hooking the horizontal bar each time. Pull this tight to close the seam but not so tightly the fabric ruches.