No bootable device creating new cube from USB

I am trying to create two new Qubes from bootable USBs I have created for Windows 10 (created from the Windows Media Tool) and Ubuntu (created from Rufus) via Qubes Manager. My bootable USB shows up in the list of devices to boot the Qube from when I initially create it, but whenever I start it up I get “No bootable device” from the black screen within the new Qube.

This occurs for both Windows 10 and Ubuntu. I’ve confirmed both of these bootable USBs were properly created and they are showing up correctly in my device manager. Does anyone have any ideas as to how I can correct this and boot a new Qube from a bootable USB?