You are using Legacy BIOS or CSM if you follow those steps to bypass UEFI. That's why changing the BIOS settings is a first step.
UEFI is completely cut out unless you use CSM Dual Mode which allows Dual Mode choice to mix UEFI and MBR installs.
This is new enough that while some are opting to Bypass UEFI using those steps, it remains to be seen if that is the Best Practice given that UEFI offers some promised advantages and is where BIOS are heading. You'd have to compare to know what these advantages are until there is more reported for your BIOS. We are only providing the steps for users who don't care about UEFI and just want to get installed.