The reference edge is covered, preparatory to positioning of the table, by the doubled flap which is folded atop one of {HEAD ~ first pair} of {TAIL ~ stacks} 
The reference edge is covered , preparatory to positioning of the table , by the doubled flap which is folded atop one of { HEAD ~ first pair } of { TAIL ~ stacks }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL