Enable or disable audio automation and choose MIDI controllers for audio automation from the Audio Automation dialog available from the control area in the Audio Mixer.
Checking Automation will enable Audio automation. When audio automation is enabled, each audio tracks fader is controlled by the MIDI controller in the Fader drop-down list box and each audio tracks pan pot is controlled by the MIDI controller in the Pan drop-down list box. The channel for this MIDI controller is the same channel as that tracks channel set in the Track Sheet.
In addition, when audio automation is enabled, you can record and play back fader and pan pot movements on each audio track strip. Record fader and pan pot movements on track strips by pressing the Record button in the Main Transport, and then moving faders and/or pan pots on track strips. Controllers will be recorded to each track on the same channel as that tracks channel set in the Track Sheet.
This means that you can use an external mixing board that sends MIDI controller messages when its faders or pan pots are moved to control each audio tracks fader and pan pot. You can also use MIDI controllers on each tracks channel for the same purpose.
It is also possible to use audio automation separately with any VST instrument or effect that supports it. The MIDI commands that a given VST instrument or effect responds to will depend on that instrument or effect. Refer to the instrument or effects documentation for details of its audio automation implementation.