I tried for a bit to do it myself but it did not work. 2020 VS03 with the MBUX 10.25". Went to the dealership and they did it with their system. Seems there is some confusion about what app to use. Here is what I learned... You use the Mercedes Me Connect app, Not the Mercedes Pro or Mercedes me app.... It has to be the "connect" app. Verifying the vehicle manually by entering the VIN does not send a code to the MBUX display like it says AND there is no QR code to scan in for the automatic verification option (the rescue QR code and the tiny QR code on the VIN sticker do not work). I sat there for 40 minutes watching the MBUX display for a code... Nothing. Went to the dealership and explained what's going on... They said MBUSA is implementing some back-end system changes and that the system is not completely working correctly at the moment. They had me delete the app and reinstall it.. I created a profile and then they manually entered and verified everything and in 3 minutes my app was working and connected to the van.. Got it all, Tire pressure, DEF level, Fuel level.... Everything is working and all of the app features are there. You do not need an internet data plan on the MBUX to make it work... The van has it's own telematics system and can send and receive data without a paid data plan. The data plan option is there if you want to have a mobile hotspot.
You will receive all system and map updates without having the optional data plan.