Well the original English language file is here: https://github.com/PhantasarProductions/House-Of-Cards/blob/main/SRC/Assets/Tric...

Basically it's just FIELD=Text so basically it's just replacing all texts behind the = mark on every line with their English translations.

Only this part can best be left alone:

[^SYS^]
ACTIVE=Yes
CREATIONDATE=2/2/2024 10:18:07 AM
CREATIONTOOL=Rosetta

And in this part:
[LANGUAGE]
NAME=English
TRANSLATOR=Jeroen P. Broks
You can replace "English" with the Indonesian name for the Indonesian language, and in the TRANSLATOR field you can enter the name of how you wish to be credited as the Indonesian translator.

I hope that's all simple enough to understand. Thank you and good luck.