This tutorial is the same for sessions that haven’t been setup yet, and for sessions that only have MIDI recorded in them. Changing the tempo of sessions with pre-recorded audio is a separate tutorial.

When you start a new session in Pro Tools, the tempo defaults to 120 BPM. To change it, insert a tempo event at the beginning of the Tempo track.

1. Double-click the Song Start Marker in the Edit window.
2. Enter the BPM value you will use for the session and set the Location to 1|1|000 (so the inserted tempo event replaces the default tempo).
3. if you want base the BPM value on something other than the default quarter-note, select another note value from the Resolution pop-up menu.
4. Click OK to insert the new tempo event.

If you have pre-recorded MIDI events/tracks, the tempo of those tracks will automatically follow the session tempo.