Translating NeoLoaders GUI is quite simple,
there is a very detailed guide at: Qt Linguist Manual: Translators | QtLinguist | Documentation | Qt Project
To summ it up you open the translation file in the linguist tool and start translating strings that are presented to you in the tool.
%1 %2 etc.... are placeholders for for example filenames or other data that have to be also in the translated string but you can change their order.
You need to install QT what is a little bit big, so I uploaded the linguist tool only in a zip: http://update.neoloader.to/all/QtLinguist.zip
You only need the linguist tool from QT to start translating + a translation file for your language: already started files can be downloaded from: http://update.neoloader.to/all/Translations.zip
If you want to contribute and start a new translation just tell me the exact language and I will add the file to the archive.