The Microsoft Surface uses its own unique interface for booting into the UEFI firmware interface.
First, you need to access your BIOS / UEFI setup utility on your Surface.
Make sure your Surface or Surface Pro is fully powered down.
Press and hold the volume up button located on the left side of the device.
Press and hold the power button for five seconds located on the top of the device.
Release the power button after five seconds but continue to hold down on the volume button until you see BIOS UEFI.
The Surface uses a combination of text-driven interface, touch and mouse input to modify boot settings. Navigate down to the option Configure Alternate System Boot Order using the down arrow key. Hit the Enter key, which will load a sub menu; use the up and down arrow to select the first boot device then hit Enter.
Navigate down to the Exit setup menu, hit Enter, use the left or right arrow keys to select yes then hit Enter.