Phone holder
The Seat Mii has a clever phone holder. Underneath the phone holder, you'll find two buttons. To set the upper arm to the home position, press the button on the right, allowing the phone to be inserted and removed.
The button on the left is a little harder to find. It doesn't stick out as much.
Use this button to adjust the phone holder to the width of your phone.
At the back of the phone holder, you will find a USB connector.