Loosening the pinch bolts lets the fork tubes re-adjust and align to the pressure the fork brace puts on them. It's very easy to do with a 12mm socket. I believe it is also recommended to bounce the front a couple times with the pinch bolts loose. If you have a torque wrench, retighten to 12 lbs. If not, tighten the bolts snug but do not tighten as much as possible. You can get away without loosening the pinch bolts but, the trike will likely handle better in the turns if you do.
Yep it recommends bouncing the front a couple times. The install is actually quite simple, only took me about 10 minutes to install one on my 2012.