Installed Windows 10 in UEFI mode. How do I disable it?

Not sure if that title is correct, but when I went to the boot menu to choose the drive, I chose the flash drive with the installer on it, but the one that said "UEFI" before it, not the USB one. Now my windows logo has been replaced with the ASRock logo and when trying to install lubuntu (dual boot alongside windows 10), windows isn't recognized as an OS like it usually is and it's having trouble installing even when I go to the "something else" option to select/create the partitions manually.

I feel dumb right now as some sites have suggested I disable "Secure Boot" in my BIOS settings, even though it's already disabled.

Not sure if it would matter but my specs are

Intel Core i7 3770k

16GB Corsair Vengeance Pro ram

Samsung SSD (for windows)

WD Blue 1TB drive (for linux)

ASRock Z77 Extreme4 Motherboard

AMD R9 390x (msi) graphics card