If you have experience with software development you should learn how to build the source. This is pretty easy on Linux or Mac systems. If not then skip this step and generate the file to translate from the source code by following the instructions below.
Using the Terminal change directory into the languages folder
Generate the latest strings XML
lupdate -pro PhotoFiltreLX.pro -ts en.ts
Copy the en.ts file to a location of your choice. Now rename to something else such as de.ts (for german)
Replace the strings in the file like the below example
Finally generate the .qm file that our application will use