Attach the Airdata Flowhood to the top of your Airdata Flowmeter. Check the vent you are testing to make sure air is coming out.
Place the opening on the top of the flowhood over the opening of the vent you are testing.
Set the switch on the flowmeter to its "On" position and grab the flowmeter by its lever, located above the display. You can now read the output concerning the flow from your vent.