The buttons that float on the chart are Scroll, Tempo, Zoom, Draw, Play, Key, and Rewind. You can change which buttons are shown, and where the buttons appear, in Edit Floating Buttons.
Auto Scroll, Tempo, and Rewind can also sit on the app bar. Button taps and long-press work the same in both sets of buttons. When the app bar is hidden, the floating buttons show the colors that the app bar buttons normally show (auto-scrolling status and flashing tempo).
Tap to run auto scroll. This works in scrolling display mode. Otherwise the button says Requires scrolling mode.
At the end of a page the button becomes End of Page (or Paging Delay if auto-paging is enabled). Auto scroll restarts when you move to the next song in the set list.
Tap to start or stop the metronome. Press and hold to open Set Tempo: Current and New tempo in BPM and duration, Tap Here to set the tempo by tapping, and Auto-set Duration when the song already has a duration. Tap the new duration to set it yourself.
Tap to show Current Zoom as a percentage. The button is replaced by Expand, Shrink, and Reset. Round buttons use the matching icons. Tap outside that group to bring the other buttons back.
Tap to draw on the chart: Draw, Highlite, Erase, and Pan.
Tap to start the audio attached to the song. The button label becomes Pause. Tap again to pause. Once a track has been started for a set list, the button stays green. Press and hold to open Select audio track, and choose Play pad or Play custom track.
Tap to open Change Key: the key, the capo, Capo key when a capo is on, and Transpose chords.
Tap to return to the beginning of the set list; disabled when auto-scroll is active, to prevent an accidental rewind while playing a set list.