You need to unpack the fiberglass battens. Feed the battens up through the attic opening to an area that you will not be working on . The battens are sized to fit within the cavity created between the floor joists. Normal spacing of the floor joist are 16 " on centers. The battens are sized to account for the width of the floor joists so they will be smaller than 16".

Fill the opening with the paper vapor barrier facing down. You can just but the ends of the battens and continue. Be careful when moving around the attic so that you do not punch a hole in the ceiling below.

Work your way back to the access opening. I was working by myself, so I needed to make several trips up and down the ladder to get more material. The work will go quicker if you get some help with loading material.