Hello,
Yes, we are having problems with the wiki.
If you already have Windows 10 there is chances that it uses the UEFI mode. In this case, you have no choice to install Mageia you must install it in UEFI mode using Grub2-efi.
Before the Mageia installation, you have to disable the secure boot in the firmware, and in Windows, disable the Fast boot and shutdown Windows, no hibernation.
Then you can boot on your Mageia DVD or USB stick, the first screen you get must be this one:
with this screen, you can go on, if you have another screen with a menu in the bottom, there is something wrong.