How to set up a custom paper size MF744 printer

[Barvas11]

Hello,

I cannot set up a custom papers for MF744

It says Custom [fixed name] in the menu which is set to A4 paper size. There isn't any pop up window that will allow me to change the custom size as it's explained in most of the videos online. It seems like Canon has a new printer properties page and does'nt work as it used to. I couldn't find any information that would explain how to load a custom paper size in this printer......