Once registered, you have to pair your device (trainer, bike, heart rate monitor, etc.) to the Simulator. To do so, the first time you open the Simulator, the following screen will be shown, with the two communication technologies that you can use, ANT + and Bluetooth, shown as activated or deactivated in the upper left.
Once you select the brand of trainer or bike you are going to pair, you are taken to the next screen.
In the upper left you will see the two communication technologies you can use to pair your device. The rotating arrow around them means that the simulator is scanning for devices to connect. It is perfectly normal for the Simulator to try to find a trainer or bike via Bluetooth and ANT+ at the same time.
When the Simulator finds your trainer or bike, select it by clicking on the circle on the right.
Once your trainer or bike is paired, you are taken to the final pairing screen. If you pedal, you will see how the values of power, cadence, speed, etc. change. That indicates that the trainer or bike is properly paired. Click on "All Done". You can now choose the session you want to ride.
Remember that you can always open the Simulator pairing menus from the main screen.