Recording a single track of audio, is set up the same way as recording multiple tracks of audio. Use the Audio Record Input Select column of the tracks window. The default L, R or L&R settings will use the default device and channels as setup in the device options accessed from the digital audio setup dialog.

1. While holding down the <SHIFT> key, click in Record column of each track you want to enable for recording. To deselect a track, just click it again while holding the <SHIFT> key.
2. In the Audio Record Input Select column: To use the default settings from the Digital Audio Setup dialog choose L for Left (odd track number), R for Right (even track number), or L + R for Left and Right (odd and even). Alternatively select the device and channel(s) from the popup. Any setting that has '1+2' or 'L+R' automatically enables this track for stereo recording. Otherwise the track is set to record monophonically. The Audio Record Input Select column is shown or hidden using the little downward pointing triangle popup directly above the track numbers.
3. Click record in the transport window to begin recording.

For versions prior to 6.0.8:

The main difference between recording single and multiple tracks of audio is how you set the record source. When recording a single track of audio, you choose the audio recording device (record source) from within the audio options dialog, under the Setup menu. When recording multiple tracks of audio, the output device = input device so you set the output (instrument) port to the device you want to record. With this in mind, here’s how to set Metro to record on multiple tracks:

1. While holding down the <SHIFT> key, click in Record column of each track you want to enable for recording. To deselect a track, just click it again while holding the <SHIFT> key.
2. Set the output device (instruments column) to the input device and port you want to record with.
3. In the Audio Record Input Select column, choose L for Left (odd track number), R for Right (even track number), or L + R for Left and Right (odd and even). The Audio Record Input Select column is shown or hidden using the little downward pointing triangle popup directly above the track numbers.
4. Click record in the transport window to begin recording.