First of all, you need a MINI ID. If you do not yet have a MINI ID, follow the welcome message on your vehicle's control display. As soon as your MINI ID is registered, it is automatically added to your vehicle. If you already use the MINI app with your MINI ID, and you log in to a MINI with it, the vehicle will also be automatically added to your garage.
As soon as your MINI is connected, you can start the registration for MINI Charging directly via the MINI app. To do this, select the 'MINI Charging Account' tab under 'Charge here'.
You can find a how-to video on the registration process here:
Alternatively, you can register with your login details for the electric vehicle charging service via https://mini-charging.com.