Turn the chair upside-down and unscrew each leg, removing them completely. You should be able to unscrew the legs by turning them with your hand. Set the legs aside.
Inspect the bottom of your chair to ensure there is enough space under the seat to accept the glider mechanism.
Measure the inside base of your chair and cut the hardwood strapping to fit. Attach the strapping to the inner sides of the chair base by drilling pilot holes and screwing into the chair frame. Build up the strapping until the central opening in the chair is snug enough to attach the glider mechanism.
Align the glider mechanism in the base of the chair. Mark the strapping with a pencil to show where the screw holes to attach the glider mechanism will be located. Remove the glider mechanism from the base of the chair.
Drill pilot holes in the hardwood strapping at each mark. Replace the glider mechanism in the chair base and align it with the pilot holes.
Screw the glider mechanism to the chair base.