Nov You can attach wood sleepers to the floor, fill the gaps with rigid-foam insulation, and then apply your finish flooring. Or, as demonstrated here.
Secure each sleeper to the floor with the proper fasteners. Someone holding a caulk gun applying adhesive to floor sleepers.
STC Acoustic Sleeper is a cost effective and STC rated isolation pad for isolating sub- floor, stages, risers, and other similar assemblies for quality floor.
This was therefore the "cut line" for any sleeper on the floor. This is more clear in the photos below. To build the supporting structure, start by installing treated 2xsleepers on the flat on top of the poly. Place the first sleeper inches in from the edge of the walls.