No bootable device

[Saltgrass]

Make sure you check the Main page and I assume you still have Secure Boot enabled.

Some Bios options can change based on what is currently selected. Disabling Secure Boot may show additional options.

 

[Ethan]

The options on the main page don't change if I enable/disable secure boot.

 

[Ethan]

All that changes is that it lets me choose what happens with secure boot.

 

[Trouble]

Changing "Secure Boot" from enabled to disabled and saving, should allow you to boot to your USB installation media.
IF not there might be a problem with the USB port that you are using.
I did read some things that owners of some devices were having issues with the USB port on the keyboard and needed to purchase an OTG adapter cable to use the micro USB connection to boot their devices.

Does your device have an SD card slot? Have you tried putting your installation media on an SD card and attempting to boot from that, if that is even an option.

 

[Ethan]

That's probably not the issue.

 

[Ethan]

There's no SD card slot anyway.

 

[Trouble]

OK.... IF you say so.
I would suggest that you then try downloading another ISO to produce another instance of installation media.
Perhaps trying something a bit more main stream like
https://linuxmint.com/edition.php?id=219
See if that will at least boot and run the Live Distro version. No installation is necessary.

 

[Ethan]

I can't. My computer can't boot Windows.

 

[Trouble]

I can't. My computer can't boot Windows.

I think we've pretty much covered that and we're clear that your computer is not booting "Windows" nor apparently anything else.
Do you have access to a second working machine (neighbor, friend, relative, cyber-café, etc.,) that you can use to produce the boot media?

 

[Ethan]

No I don't.

 

[Trouble]

Sorry......
I think it's time to contact the manufacturer and see if they might be able to provide you with installation / recovery media that will work.
Usually it's free if the device is still under warranty and a nominal cost if the warranty has expired.