Why do I not have air flow after replacing front blower motor on my 2004 Honda Pilot?

I just replaced the Front blower motor last night. With fingers crossed, I started the car, turned on the heat and.... nothing except I could hear the blower motor spinning and change speed when I increased it on the heater/ac control panel. There is no air at all coming out of the vents. Could you please help me to identify what might be going on and a way to fix this? This 2004 Honda Pilot has not had air flow or AC for years and I replaced the blower motor just last night thinking that was it being that a mechanic told me that was the problem. He was obviously wrong so could you help? Thank you.