There are some prerequisites before you can start:

• The trainer must be connected to the Android device via TCP/IP, USB or Bluetooth
  
  
• Your Android smartphone/tablet must be connected to the local area network (LAN) over Wi-Fi, that's necessary to connect to zwift, bkool, strava etc.
  
  
• It may be necessary to configure an ANT + connection
  
  

The configuration menu can be reached via the settings button of the app..

The procedure differs according to the trainer used.