1. Mute the Tracks you want Muted.
You can use either the Mute function or the Solo function, as described in the Getting Started manual.
2. Hold down [Shift]+[Alt] and press one of the keys [1] to [0] on the typewriter part of the keyboard.
The Mute setting is now stored under that key.
P Remember that all Key commands can be customized! The key combinations mentioned above are the default key commands.