If you already have the video files and just need the subtitle files (.srt), you can check dedicated subtitle repositories:
: A popular site for Balkan language subtitles (Croatian, Serbian, Bosnian). The Simpsons (1989) Hrvatski, Engleski titlovi
It refers to the original 1989 series created by Matt Groening, which premiered on December 17, 1989, with the Christmas special "Simpsons Roasting on an Open Fire". If you already have the video files and