This project stemmed from trying to make it easier for my son to mount arbitrary pieces of equipment to his bike handlebars. He builds all sorts of little things, and the hardest part is always clamping them securely but still easily being able to pull them off to upgrade. And even if they fit on his bike, would they fit on different one?
First attach the two center bar clamps on either side and as close to the center post as possible. I used a 3/16 1" bolt and nut to secure the camps, you might want to go a little longer, say 1 1/4" though. Loosely bold them in place but do not tighten them up yet.
Next place the clampbar over the handle bar clamps and center it then tighten down the bar clamp bolts. the clamp bar has many different attachment points all over it's surface to attach things to.
Clip the clips over the posts to secure the whole assembly in place.
If you want to take the assembly off just remove the clips and pull off the clampbar while leave the handle bar clamps where they are.
To ensure nice strong parts I recommend printing with 2 shells 25% infill and .3mm layers.