Hey felepino! I moved your question to the proper section, that makes it easier to find in the future.
In order to translate Edain, you first need FinalBig to be able to edit the game files. Then, you have to edit a file called lotr.str where you can find every text that is used in Edain. I have to warn you, though: There are a lot of them. If you are serious about this project, I recommend using the help of online translators like DeepL and then checking if everything is correct afterwards. Translators have some problems with certain names in Lord of the Rings, but they will ease the workload tremendously.
Welcome to the forums!