[NumberSix]

You should have found a little booklet inside the jewel case they sent you.

Basically, you get in the car, turn it on and insert the USB into the glove box port.
When the system identifies the stick, you can click on "Start Update"
Provide the 20 digit code and click "OK"
When finished it will display "restart the System" and then with the iDrive click "OK"
Remove the stick and use it for whatever you want. It is a 32G USB so it would hold a lot of music.

BTW, DO NOT remove the USB until the update is completed. You can power down the vehicle and the update will resume on the next key cycle.

Your dealer should also have the booklet or, at least the instructions