Question: how to pair your apple iphone to your mercedes-benz bluetooth system (hd)?
Answer: Step 1 (to be performed on your Apple iPhone 6) ... 
To get to the telephone screen of your Mercedes-Benz hands-free system press the “TEL” key on the radio or select "Phone".
Select the application "Connect Dev." located in the lower left corner. ... 
Select the "Search for Phone from Vehicle" function.