The video was very helpful in showing how to properly replace the motor. However, it should be noted (and I don't know if I missed it in the video) that the threads to the fan are reverse threads, in this case,,,,righty loosey, lefty tighty. On a 15-20 year old dryer it is probably expected that you will not be able to break this loose from the threads without damage, so expect to have to replace the fan as well.
Also, you can't say enough about the speed of delivery, I ordered the motor at 3pm and it was on my doorstep at 9am the next morning. Between the ease of finding and ordering the correct part, the helpfulness of the website and the speed of delivery, this has to be one of the all time best online services out there. Nice job Appliance Parts Pros!