For translating, you need to have git and the Qt Linguist tool How to install and use git Download Qt Linguist
To add a new language you need to use the ISO 639-1 code as the file name, for example Portuguese (ISO 639-1 code "pt")
Copy the en.ts and rename it to pt.ts
cp en.ts pt.ts
Open the file with Qt Linguist to edit them
linguist pt.ts
When you've finished create a pull request.