1. Hi. Start by turning off the phone. To do that, press and hold the Power button.
2. When the phone is turned off, press and hold Volume Up & Power buttons.
3. Let go of these buttons when a Boot mode menu shows on screen.
4. Select Fastboot option. To do that, use Volume Up to navigate and Volume Down button to confirm your choice.
5. Fasboot Mode has started. It can be navigated with Volume Keys (movement) and Power button (selecting).