1. Press & hold the Power button to power down the phone.
2. Hold down the Volume Down.
3. Still holding down the button, pick up a micro USB cable and use it to connect the phone to a PC.
4. Fastboot mode menu will appear on screen. When it does, release the aforementioned buttons.
5. Fasboot Mode has started. It can be navigated with Volume Keys (movement) and Power button (selecting).