I assume everyone knows this and I am merely slow.
Just in case.
When you purchase a dvd from Gnomon you must install
( or have already) certain programs to make it run
When the dvd starts there is some music, table of contents which you
must pick what you wish to watch. You select and then the lesson plays.
Some of the lessons are a little long ( half hour, to an hour).
As you watch them there are no provisions for pausing.
You generally speaking cannot work along with the lesson.
If you stop to try and duplicate the activity you must basically start all
over again, which can get annoying.
Music, although good, gets tiresome.
However.
If you open the dvd and go to bin>misc>generic files> you will see the lectures as quicktime movies.
If you copy them and paste them to your desktop you can work along with
the instructor by playing them as quictime movies.
Obviously it helps to have quicktime ( free download)
If in generic files you see nothing, change the folder options to read
show hidden files.
Although it sounds like a lot, you can set it up in just a few minutes.
The time saving and conveniece and learing ability makes it worthwhile.
As I said, you knew it anyway.