Hi @Katya_u,
Here is information in Ukrainian about what you need to do with your car that you brought to Germany:
https://hilfe-ua.de/ua/informatsiia-dlia-ukrainskykh-vodiiv/
It explains that you need to make sure your third-party liability insurance is valid and that you must register your car in Germany within 12 months of coming here.
Best,
Éanna