If access to the outside of the sleeve is easy, stand outside and place the screw-head bolts with
washers back through the keyed holes and drop down to lock in place.
If access to the outside of the sleeve is difficult (such as on a 2nd floor), pass the grille through
from inside the sleeve, and work the screw-head bolts into the keyed holes.
Tighten all 6 bolts from inside the sleeve to secure the grille.
