If you are changing the tensioner my best advise will be to do it from below the car like I did twice...
Just jack up the front axle (No need to remove the wheel) and do the job from beneath once you have removed the belt.
After you replace the tensioner then lower the car and replace the belt, its pretty easy.
The TL video is pretty accurate as is the same tensioner design. The main difference is the gigantic room you have in the TL due to the engine sitting leveled to the car body, The MDX engine sits far lower into the engine bay which makes it more difficult to replace the belt.
In my personal scale of DIY its a 4 out of 10.. Pretty average in difficulty, Should take no more than 30 minutes the first time.