Once you have the materials you can begin to seal and insulate the knee wall access door through these steps.
How to seal attic access panel.
Pray that the installer used finish nails and not say ring shank nails.
Apply weather stripping to the door to create a seal.
Apply self adhesive foam weatherstrip tape to the top edge of the stop.
The stops provide a wider surface for attaching the weatherstrip and a space to mount hook and eye fasteners.
How to air seal attic access panels.
Air seal the trim the first step is air sealing the finish trim and enclosure around the attic hatch.
The trim should extend one half inch to one inch around the inside edge of the access hole forming a ledge.
The access panel will rest on this trim.
Install weather stripping along the top of this ledge.
Cut 1 3 boards to fit the perimeter of the opening and nail them on with 6d finish nails.
From inside the attic check for any openings holes or fenestrations into the knee wall surrounding area.
Carefully pull down the finish trim.
Seal the attic access weatherstrip the attic access hatch or door.
Install wood trim pieces on the ceiling side of attic access hole framing.
Sealing the attic hatch or door finish up by sealing the access hatch with self sticking weather stripping.