hi @3dmakeres.
First of all, you should have a look to the correct topic. That one is only for the development.
Then you can try this excellent video, that explain how to compile Marlin for our printers: https://youtu.be/ysfZrPnJAvk (in french)
Then, before the compilation, in the "configuration.h", in addition of the lcd version of your printer, the printer model you use, you should modify the line "#define LCD_LANGUAGE fr" to what you want.
fyi, All language files are in the github: https://github.com/hobiseven/Marlin_2.0.X_Beta_Alfawise_Ux0/tree/master/Marlin/src/lcd/language