UEFI problems setting boot options

Have a 7773 using UEFI, bios. I can't find anything that helps me get the boot sequence or F12 to see USB. Tried turning off secure boot and turning it back on. Nothing changes. Does not see or list the drive in boot up menu. Any help would be greatly appreciated. Need to clean install Windows 10 from 11. It's been 3 months since it was upgraded. System very slow. Want to go back to !0 for now since laptop not in list to support 11.