Attach the flex to the vent with the provided screws. From the outside, push the flex through the 6 ¼” hole.
Make sure the vent is not twisted by inserting the screws too tight and that the flaps are working properly. Attach the vent to the outside wall with the provided screws
From the inside measure the distance between the elbow and the flex. Cut off the excess flex. If this is not done, the efficiency of the unit will diminish drastically.