Nail Free, the way to be !

A dab of construction adhesive to hold the piece of trim to the blocking, a bead of wood glue to hold the joint together..
and soon you'll have some nice looking flooring on your ceiling !!!

Hope to be done today.

And it's not really "nail free", the trim is nailed thru the tongue (the floorings all "tongue and groove") and the miters are glued in place, so it looks nail free !
(For HKI)