Remove the screw from the knuckle using a flat tip screwdriver.
Pull the rim ends out of the knuckle and mark the base of one of the rim ends with a black marker (this may have been done for you during manufacture) and mark the hole on the knuckle this rim end came out of.
Once you have fed the net bag onto the rim and replaced the ring in the same position you must insert the rim ends into the same knuckle holes they came out of.
Before you insert the screw you must ensure that the rim is fully inserted into the knuckle and you see a continuous ‘thread’ for the screw to follow.