The soft boxes collapse down for storage. To set up, remove it from its bag and set it on the ends of the rods as seen here. Note the tabs on the back of the metal ring. These are locking tabs for each rod that supports the soft box.
Standing over the soft box, pull each rod towards you until it is perpendicular to the ring, you should feel or hear a click as it locks in place. This will tent out the fabric of the soft box and hold it in place.
Close the velcro over the rods to prevent light from leaking out the back of the soft box.
It should be attached to the rear of the soft box already, but if not, attach the Bowens mount adapter, which is a black metal ring with three notches that correspond to the three metal tabs on the back of the soft box. This too will click in place as you place it on and rotate slightly.
The front of each light features four hooks to hold on to the adapter on the back of the soft box. To install a soft box, pull up on the top hook and rotate it 90 degrees out of the way. This allows you to slide the adapter in.
This configuration allows you to freely slide in the soft box.
There are two sets of notches you can slide the soft box into, the ones closest to the front of the light are preferable. Once you slide it in, pull the top hook up and rotate back to its original orientation. This will secure the soft box in place.