At least two frame engaging {HEAD ~ members} of {TAIL ~ the frame support structure} are then moved to position side members of the frame to a desired configuration 
of
At least two frame engaging { HEAD ~ members } of { TAIL ~ the frame support structure } are then moved to position side members of the frame to a desired configuration
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH