How to open, edit and save XLIFF file

Hello,

following the steps named in this article https://community.articulate.com/articles/rise-360-translate-your-content
I was testing the translation functionality. I exported the XLIFF file, opened it in notepad, changed some sentences into a newly translated ones (all this was done just to test the whole process), I saved the file and imported it back to a copied course in RISE. Unfortunately, nothing happened... the translated sentences were still in original language - english.

Is it possible that notepad is not saving the file in a correct format? Is there any free software (or MS Office software), that I could use to open this kind of file in a user-friendly way and then save it in a correct format?
I tried Excel but it doesn't seem to work either, the result was the same. (maybe I need to change some settings in Excel?)
I saw some people proposing SmartCat software, but I noticed it isn't free anymore. Is there anything else?

Thanks for any help. It will be much appreciated.
Wojciech