1. Hello. Please press the Power button to turn your phone on.
2. Now press & hold the Volume Down and Power button for a few seconds.
3. Using Volume buttons to select and Power button to confirm, select Reboot to Bootloader.
4. Use Volume buttons to select Reboot to Recovery Mode. Confirm with Power button.
5. Good job, you are in Recovery mode. Navigate it with Volume buttons; select options with Power button.