Like HD, I have yet to find one video on youtube that does a good job on room correction with Audyssey, Dirac Live or Anthem ARC. One just have to read a ton of stuff. Having said that, just to learn how to run such calibration, you only have to read the owner's manual and follow the instructions.
It is to learn how to get the best out of such RC system that takes time to read more and experiment more. As far as setting LPF (Audyssey's) to 120 Hz, that has been a good guideline for years, and there isn't a good reason to go lower, or higher though going higher wouldn't change much if any, just nothing to gain.
If you want to get more from Audyssey, there are some good articles, guidelines etc., on the internet but many of them are filled with bad information so you need to be careful choosing what to read and believe. Below is one of the better site, I don't agree with all of things they said, but over all, they have done a good job. Please take the time to explore the site and read some of the other linked articles.
Configuring Audyssey – The Right Way – Simple Home Cinema
They apparently also sold a spreadsheet based UI that will let you take full advantage of Denon's $20 Mult EQ Editor App. I used Ratbuddysssey that is free but that could be a little complicated for a lot of people. Based on the information provided on this Beta product, I think it may not have as much flexibility of Ratbuddyssey, but would be easier to use so I wouldn't mind paying a reasonably fee for it. The author also provided a link to Ratbuddyessey at the bottom of the page.
Audyssey Curve Editor Excel Tool – Simple Home Cinema