We start by connecting your iPad to your computer.
If you're using a MAC, open "Audio Midi Setup" and the Network Settings.
If you're on a Windows computer, use the free rtpMidi software by Tobias Erichsen.
Make sure you have a Midi Session. If not, create a new one and give it an appropriate name.
Start the m.phase Application.
You should now see your iPad in the Midi Setup dialog on your computer.
Select your iPad and connect it to your computer.
Connect your iPad as a Mackie / MCU Pro to your Bitwig Studio software.
Do this by opening the Preferences dialog in your DAW.
Click on the Controllers section of your preferences dialog.
Now add a new controller with the type Mackie / MCU Pro.
Make sure that you have set your MIDI session as an input and output for all MIDI messages.
That's it, save your settings and you're ready to go!