It's pretty straight forward. Take the lock nuts off the hull stud on the upper inside gunwales. Loosen the lock nuts on the V-Truss and turn the turnbuckles to shorten the rods on each side. Shorten only enough so that the upper mount slips off the hull studs.
Now remove the V-Truss mounting nut on the bottom of the receiver.
From there you should be able to follow the obvious removal of the nuts and screws holding the receiver in place.
When you reinstall the V-Truss, don't overdo things. Put things back in the reverse order of the above, only turning the turnbuckles enough to exert snug pressure against the hull. Don't use so much force that you distort anything. Instead of doing one at a time, bring both up equally, turning one a little, and then the other a little, so on and so forth.