Cut a 3 7/8 x 12" pcs pattern paper.
At one end cut 1/4 x 5/8 x 1/2 U shape.
Attach this 1st fold over the remain and tuck over.
You may need to trim w/ a craft knife.
I finshed off the seam by placing a thin decortive strip over the top.
Hope this helps. Let me know how yours turns out.