Indesign & Excel translation

So I received a Indesign document which contain 176 pages. Each page contain 10 questions and 10 answers all in english. I also got an Excel document with the same questions and answers in english, with very strict instructions on how to change the english language to German. The translation is now done and I know have the Excel document in German. I now need to change the Indesign document to German instead of English. I assume there is a way to import this Excel document and somehow automatically change the english language to the German. I have no idea how, since I'm pretty new to Indesign, but since the instruction on how to change language in the Excel document was very strict and had to be done in a certain way, it means that it has somekind of connection with the Indesign document.

But how does it work?