the BMW manual explains it very well -- the only thing you need to know beyond that is...
on the 710 you find the "activate bluetooth" link by going to the main menu (center button) > Settings > Connection (last on the list) > Bluetooth Link.
Enter any code name you like for the phone -- it really doesn't matter
Mine worked right away but others have had problems with this phone.
If it doesn't work, you might need to have your phone's firmware upgraded which the carrier should do for free. I had mine upgraded last April by Verizon.
325xi | Prem pkge | iDrive | Sirius | Cld Wther | Step | In-service: Nov '05 | As of May '14: 129K mi.