How to Make a Box Kite

Fit the shorter cross-piece as in the top photo, between the unmarked spars. Wrap a small square piece of electrical insulation tape around where each tip touches the spar.
Trim the longer cross-piece a little at a time until you can slide it completely into position between the marked spars. It's OK if the marked spars are pushed apart just a little. Put a drop or two of wood glue at each end to secure it, as in the bottom photo. At this point, the two cross-pieces should be holding the kite open, with all the plastic panels under a little bit of tension.
When the glue is dry, flip the kite over and add some more glue to strengthen those joins on the other side.

Dacron line in 20 to 50-pound strength is suitable for all the Skewer Series kites.

Poke two holes in the plastic of a cell, 0.2 SL (5.8 cm, 2 1/4 in.) from the tip of an unmarked spar. Make one hole on each side of the spar.
Cut off a length of Dacron line, about the length of one skewer, and tie a small Loop knot into both ends.
Attach one end of this bridle to the kite, by passing it through one hole and out the other, and then through a loop. Reinforce the sail near the towing point, with a short strip of sticky tape.
Cut off four squares of electrical insulation tape and cap the spar tips nearest the bridle.
Now tie a loop of flying line around the two marked spars, which you can also see in the photo, labeled tensioner. Try to pull just enough tension into it to keep the lines straight, and tie off with a few Half-Hitches.
Put a small drop of glue on the tensioner knot.
Also put some glue where the cross pieces touch each other, to keep everything stiffer.

Cut off several loops of plastic from a dark garbage bag, and knot them together to a length of at least 3 SL (90 cm, 35 in.). The width should be about the same as two adult fingers, or a little more.
With sticky tape, attach one end of the tail to the lower tip of the spar to which the bridle is attached. This should be clear from the flying photo at the bottom of this page.

At this point, you've pretty much finished making the MBK 1-Skewer Box kite!