OS boot device 
Installing boot device drives 
Procedure 
1. Push the button to pull out the carrier.
2. Remove the SSD mounting screw.
3. Insert the SSD into the M.2 slot at a 45° angle (callout 1).
4. Carefully press the SSD down to the horizontal position (callout 2).
5. Install the SSD mounting screw (callout 3).