iOS (Mac below)
In iReal Pro, go to Settings -> AirTurn and enable it.
[Pair to your Airturn device, iOS Settings -> Bluetooth]
Tap your Airturn device in iReal Pro Settings, select the function (from iReal Pro's options shown below) for each pedal (or buttons for Digit).
Options: Play/Stop, Play/Pause, Stop, Tempo (up/down), Previous/Next, none
For the iOS version of iReal Pro, Airturn provide their software which is embedded.

The more recent Airturn models work with their "Airturn Manager" (download from the Mac App Store) where you choose a mode and set key commands for iReal Pro.
[requirements: OSX10.14 or later, Universal]
Assign an iReal Pro key command (find these on the right of each command in the various menus) to each Airturn pedal/button.
e.g. choose Space (spacebar) for a pedal/button to Play/Pause; choose down arrow for another pedal/button to go to the next song (click the first song inside your playlist so focus is in the playlist's songs column so the down arrow will work)
(See mode 2)
image of Airturn manager settings as described in example

Tip: Set up a different mode for each app you use Airturn with, so you do not need to program (set key commands for each pedal/button) each time you use Airturn with each app.

Mac tech support: please contact Airturn support
(Sorry no Android Airturn support built-in)