Back in the attic, attach a 4-inch, 90-degree duct elbow to the outlet port on the side of the vent fan housing. Aim the elbow straight up and secure it to the port with foil duct tape.
Remove the knockout hole on the side of the fan's housing and attach a cable connector.
Slide the four metal brackets into the tabs protruding from the sides of the vent fan.
Set the vent fan down into place between the joists, centered on the ceiling hole.
Tip: Use foil duct tape; unlike fabric duct tape, it won't deteriorate over time.