Differential for Tiguan?
 

just bought a used 2017 Tiguan and I love it. It wasn't well maintained so I went to look up every fluid that exists to change it all and used this as a guide:
https://www.searchforparts.com/oil-c....0l-ccta-turbo

under differential there is this
0AY Rear 2.1 pints
Bevel Box 1.9 pints

I have no clue what to do. A friend will help me change the oil, transmission, coolant, but what do I do with those 2.1 and 1.9 pint levels? I searched online but it led to more confusion. Do I need to go to a special shop or the dealer (hope not) for that?

Thanks!