Below the three dots in the header at the top right of the page next to your account name is the app's menu.

This is where you'll find the RFH Help Center, among others.

You'll find a lot of information here on all RFH apps on Floriday, including RFH Finance.

Under the header Organizations, you'll see your registered administration numbers. From here, simply switch administration numbers by ticking the appropriate administration number.

The language can be selected to the left of your account name in the header.
The options you have here are Dutch, English and German.