the strap is one long strap... it goes through the connector and through the part similar to a seatbelt latchplate.
if it were me, I'd still order a new one, but this would at least be a temp fix.
you would take the loop end... feed it in through one of the slots for the tether (according to the instructions)
and out through the one at the top of the seat (the back of the seat should match the picture on the instructions)
then feed the connector, latchplate, and strap through the loop.
connect, pull the adjusting part of strap to tighten.