Even though the Tesla Model S doesn't support Apple CarPlay, you can still connect the Apple iPhone 7 over Bluetooth.
Just go to the Bluetooth screen on the Tesla display and select 'Add New Device'. Make sure Bluetooth is turned on the Apple iPhone 7 and that it's discoverable.
Once you see the Apple iPhone 7 on the Bluetooth screen, you can select it to start the pairing process.
All you need to do is confirm the PIN number that shows up on the Apple iPhone 7 is the same as what shows up on the Tesla Model S's screen, and you can start making calls and listening to music from the Apple iPhone 7 through the Tesla Model S.
Note if you need to access your phone's contacts and calendar on the Tesla Model S, you need to install the Tesla App as well.
You can easily play songs from the Apple iPhone 7 directly to the Tesla Model S by selecting 'Phone' in the Tesla's music screen.
Trying to use Apple Siri is a bit hit and miss, especially since Tesla has its own voice command button and commands.