How to add a language to a mod in english?

[Kyuss]

Hi folks,

I want to translate JNR urban complexity mods to spanish but I don't know how to do it without replacing english text, just add this new language that will be activated or not depending on your game language selection.

I have been inspecting the mod folder of "District Expansion: Military" mod and I have seen a "text" folder with a sql file containing all the descriptive text I want to translate. But I don't see any selector or any tag with en_EN saying all you are watching is in english, if so I could replicate the entire en_EN container and translating to es_ES. I must add a new xml to act as some kind of selector for the different languages or I must encapsulate the entire content within en_EN and es_ES?

Thanks