Create a folder PersonalPOI on your SD card, copy all required files to that folder (PersonalPOI), insert the SD card in the COMAND APS system, press the NAVI button and select PersonalPOIs. It is all explained here: https://www.gps-data-team.com/pda-gps-navigation/topic/7448.html
I agree, MB could make it a bit easier.
Is this what you need? We can add more custom options to that file format if you need it, advice how to use additional setup options, or fix what needs to be fixed.