You don't need to install the whole toolchains needed to build the project (Qt framework) to work on translations.

Just download http://www.softpedia.com/get/Others/Home-Education/Qt-Linguist.shtml and follow http://doc.qt.io/qt-5/linguist-translators.html

You will need to download the code source to get some context, it's probably a better idea to download from the git master repository (github must have a download as zip file somewhere) since it's more up to date than the code in releases.

If you want to test your translation you will need to whole Qt toolkit to build and run the application.

I prefer that you create a github account and upload updated files with it than you give me the file. It will attach your name to the commit make it easier to trace thing.