The first time you open the VanMoof app, you’ll be guided through a simple setup process. You’ll need to create an account if you don't already have one, and register your bike to it.
Once it's set up, the VanMoof app will automatically connect to your Smart S & X whenever you're within Bluetooth range and the app is running in the foreground or background.
If your bike isn't responding, you may need to wake it up by pressing the button on its handlebar. If this doesn't wake your bike up, then try resetting it by inserting a power bank or charger into the micro USB port on the underside of the top tube.
If your bike is awake but you're having difficulty connecting, try toggling Bluetooth off and on, and if that doesn't help then try restarting your phone. If you're on Android then make sure the location permission is granted and location services are enabled, and follow the guide at dontkillmyapp.com to ensure that battery optimisations are disabled for the VanMoof app.