I would like to make songs that change tempo(bpm) mid song is there any was to do this? So far I only know how to change the BPM of the entire arrangement. Is there a master track for setting tempo?
It can load up to 8 tracks, that is the limit for the free version. Just drag your tracks in and set some tempo markers (menu Edit > Tempo > Insert Tempo change) and activate the "Interpolate tempo to preceding marker" checkbox for a gradual change.
Click on your audio object and in the object editor go to Time/Pitch and activate the "Use musical tempo adjustment" checkmark. The audio file then stretches depending on your tempo markers.