In case you have a fritz!box router, take a look at fritz!app fon and see if that is what you want.

Here is a link to piper, which others already mentioned: https://github.com/libratbag/piper Its a software to configure mice and so on. You might wanna check out which mice are compatible with it.

Learn to get around on foot, bike, bus, tram, etc. Find out what kind of ticket is good for your. In German cities the public transportation is relatively good.

Also on sundays nearly every normal store is closed, only restaurants and some other stores like gas stations are open.