Excuse me but I don't understand how to do it. If I create the columns manually what should I name the header for the namebox of other languages? So the original is called "Name", then what should the other languages for the namebox to be?
You don't need to create a new column. Let's say your character says:
[Diana] Hello there!
So, write "Diana" to Original column, then translate it just like other sentences.
Original Japanese
Diana Diano
-> Result: In Japanese, the name "Diana" is now "Diano".
