First check that the LED of your ZBike roll is continuously illuminated; this means that it is correctly connected to the mains.
Secondly, check whether your device has an integrated ANT+ antenna; this is usually the case on some tablets and a few smartphone models. If not, in most cases you should use the ANT+ antenna provided the roller connecting it to a USB port on your device.
Since ANT+ is a wireless communication, it is therefore likely to be affected by interference. It is therefore recommended to use a USB extension cable of about 50-100 cm long so that the antenna can be closer to the roller.
If you still cannot pair your Zycle roller with the device where you have downloaded the simulator after performing these checks, it is possible that your USB ANT+ antenna isn't working correctly. Please contact Zycle as soon as possible to provide a solution.