Using the manipulating handle the display unit is wheeled to {HEAD ~ the site} of {TAIL ~ the demonstration} 
of
Using the manipulating handle the display unit is wheeled to { HEAD ~ the site } of { TAIL ~ the demonstration }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL