Changing Boot Order

I have a new DELL laptop with Windows 8.1 PRO installed. I installed imaging software on it right away, created an image of the disk, and created bootable rescue media on a USB stick.  However, I can’t get the laptop to boot from the USB stick and I believe it has to do with the BIOS boot order.  I'd like to ask for some help in changing the boot order.  I have some computer skills but feel I may be getting into an area where I need some simple, straight-forward instructions on how to accomplish this

I can access the UEFI/Boot page by pressing F12 or F2 during startup.  I'm just not sure what steps to take from that point to allow the computer to look for a USB device before the internal hard drive. Most of the selectable options in the BIOS menu are a bit intimidating to me and I don’t want to create more problems by guessing.

Dell Inspiron 5547
Intel i7 @ 2.00 GHZ
RAM 8 GB
Windows 8.1  6.3.9600  Build 9600
64 bit
Dell BIOS A02, 3/20/14
SMBIOS Version 2.7
BIOS Mode UEFI

Thank you for any instructions you can provide.

Dave…