Gather the secondary arms, the legs and the feet.

Onto the end of each leg, tighten a foot to one of its ends. Get the bolt tight enough so it won't fall off.

Insert one leg/foot into each of the outside leg holders on the secondary arms.

Adjust the height so that the top of the secondary arms will be very close to the height at the bottom of the primary arms.

Tighten the bolts in the leg holders so they are snug, but not too tight.