Take it easy Hernandez.
No need to officially translate. Just highlight and note the most important information on each document to make it simpler for the tax office to understand the document. Let’s say, if it’s you bought a house in Spain, highlight and translate the address, date, your name in the purchase contract and the purchase price.
That’s all. You can make all notes yourself. If you don’t speak German, make them in English. The Swiss tax office does speak it.
Good luck with the tax return 😁