Estes Skydart II #3229 Build, Part 18, Elevon Hinge

It's hard to turn the adjustment screw with your fingers. I used a Allen head jeweler's screw driver. Line it up with the trailing edge angle of the stab to reach the screw head.
Raise the screw almost all the way out to tie on the elastic.

Tie an overhand knot and feed it through one side of the elevator and through the stab hole.
With the screw raised all the way up, lift the elevator and pull on the elastic. Mark the spot where the elastic touches the elevator hole.

Tie a single overhand knot and leave it loose as you slide it towards the hole. I used some tweezers to work the knot close and tight against the elevator.

Cut off the excess elastic. Hang onto it, you can use the excess to replace the line if needed down the road. The kit gives you more than enough for a replacement.

Here's the finished assembly with the pop pod in place. The elevator is being held down by the retainer.