Adobe Resident Head Designer Person Russell Brown has some interesting video tutorials at
The Russell Brown ShowThey're free to download and provide a basic understanding of Photoshop Extended,
such as key commands for stuff Adobe neglected to put in the manual.
You know, little stuff such as you can bring an mp3 file into a video composition, but only if you choose File>Open As and then select QuickTime as the file type.

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And if your video has audio, you play back the audio by holding Alt/Opt while clicking the Play button on the Animation (Timeline) Palette.
My Best,
Gare