Raise the blower motor up to the ceiling, then push its plug into the electrical receptacle inside the housing.
Secure the motor to the housing with the screws removed from it earlier.
Hold the fan's plastic grille close to the ceiling. Slip the grille's mounting wires into the slots inside the fan housing.
Push up on the grille until it's tight against the ceiling.
Turn the power back on and test the fan.
Tip: If the grille doesn't hold tight against the ceiling, spread apart its mounting wires to create more tension.