Especially with such flexible modules as Feedback and Form & List more detail on customisation would be helpful.
Specifically if I was creating a form for a "Contact Us" page I would like to change the guide text:
"Feedback" to something else - perhaps "Enquiry"
the response details that the information has been "sent to the site owner"
and the text "required fields", which does not make sense until there is a page submission with errors
so knowing where to edit these texts will help

Most likely, what you are looking for is the Language Editor. This is where all of the "localized" and static text should be stored. You will find this under Admin.

Yes, my suggestion was to include in the videos details of how to further enhance / change a module / feature etc.
So in the case of the Feedback module in DNN 7, to modify the Feedback input view it is:
Admin-->Advanced Settings --> Languages --> (Selected Language) --> Site (or Host or System ?) -->Local Resources -->Desktop Modules --> Feedback --> APP_LocalResources --> Feedback.ascx