Before using the app for the first time, the tablet must be calibrated to the NOHRD bike. To do this, please open the app and connect to the bike. In "Free Training" mode, hold your finger on the top left field for about two seconds. A window with two positions opens.
Turn the resistance control to the lowest possible value and then use the arrow keys to adjust the value under "Low resistance value" so that the resistance is 0%. The same applies to the highest resistance: Turn the resistance control to the highest possible value and then use the arrow keys to adjust the value under "High resistance value" so that the resistance is 100%. Your tablet is now calibrated to your NOHRD bike.