This is an excerpt from the 📖Playback User Guide.
Playback for Mac and iPadOS supports keyboard shortcuts for the Transport controls and general navigation. Here is the list of the keyboard shortcuts defaults in Playback:
Transport Controls
Space Bar = Play/Pause
P = Pad On/Off
F = Fade In/Out
L = Loop
I = Infinite Loop
Setlist Navigation
Left + Right Arrow Keys = Browse through the song sections, when tracks are playing or paused
Return/Enter (while tracks are playing) = Confirm ReOrder to new section
Keyboard Numbers
While playing = Live Crossfade to corresponding song in setlist
While paused = Select corresponding song in setlist
Keyboard Mapping
Any keyboard key can be mapped to any mappable control in Playback. To access Keyboard Mapping mode, simply tap "Edit" in the top-right corner, and then select "Keyboard Mapping" from the edit-menu's drawer that slides out from the bottom-right side of Playback.
Select a highlighted control and then press the desired keyboard key to map the key to the selected Playback control. Then click "Done" to exit Keyboard Mapping mode.
Keyboard mapping will only be available on iPadOS if there's a connected keyboard.