If you want to get into the BIOS (actually UEFI) on a Microsoft Surface 3 Tablet follow these instructions
- Power off the Surface - a reboot is not sufficient
- Press and HOLD the Volume UP button (on the left side of the tablet)
- Press and HOLD the Power button for FIVE seconds (on the top of the tablet)
- Release the Power button after five seconds but KEEP HOLDING THE VOLUME button until your see BIOS UEFI
- Have a nice day.