It sounds like you are looking for subtitles (υπότιτλοι) for the film and likely want to ensure they are properly formatted or "cleaned up" for your media player.
I can provide specific instructions for your exact device once I know these details! It sounds like you are looking for subtitles
What is the of your movie file? (e.g., does it say BluRay, HDRip, or WEB-DL ?) does it say BluRay