Given the unique folding design of the FAR9, it is very important that you are careful when folding the front end. The HOP-up unit is proprietary and cannot be replaced with a standard M4/AR-15 unit, and if not done properly, the folding process can result in the HOP-up unit breaking.
Any damage done to the HOP-up unit through incorrectly attempting to fold the front end is considered a "user error" and is NOT covered by your 12-month warranty.
To fold the front end, remove the magazine, then pull the toggle connected to the folding arm until you hear a loud metallic "click". With this done, keep the folding arm in this position and the front end should fold to the right side and lock on the receiver lug.
If the front end does not freely fold following this process, the HOP-up unit has not retracted into the outer barrel. In this case, reset the folding arm and start again from scratch. Forcing the front end to fold without the HOP-up being retracted will break the HOP-up unit.
Folding the front end back into the ready-to-fire position requires the front end to be folded back into place and the locking arm indexed on the hook on the opposite side to the hinge. With the front end back in place, press the feed chute of the HOP-up unit through the magazine well and you will hear a click; this means you're ready to load up and get shooting!