Turn off power at the breaker
Remove the old fan if replacing one
Choose the vent location between ceiling joists
Mark the cutout opening on the ceiling
Cut the opening with a drywall saw
Install the fan housing into the opening
Secure the housing to joists or framing
Connect the duct to the fan outlet
Run the duct to an exterior vent cap
Seal duct joints with foil tape
Insulate the duct if needed
Connect the electrical wiring
Attach the fan grille
Install the light bulb if the unit has one
Restore power at the breaker
Test the fan operation
Check airflow at the exterior vent
Seal any gaps around the housing and grille