You can easily add additional addresses in the Chargee app.
Add an address
Go to Profile
Under 'Home & Energy', tap the Add an address + button
Enter postcode, house number, street and city of the new address. Also give permission to read your smart meter
Tap the Add address button
The new address has now been added. To understand the energy consumption of this address, you need to connect Sparky to the P1-port of the smart meter on this address.