With each MySense box is an EE data SIM card already installed in your home hub. This SIM card allows your home hub to connect securely to the MySense platform using 4G if there is no other internet connection available.
If you choose to use this connection method you don't need to take any further action other than installing and connecting your sensors, the home hub will find the connection to MySense for you and the data service is included in your MySense subscription.