Match the subtitle file name to your video file name exactly, except for the extension (e.g., video.mp4 -> video.srt ).
These websites allow you to search by file name (e.g., The.Villainess.2017.720p.BluRay.x264 ) to ensure the timing matches perfectly: subtitle The.Villainess.2017.720p.BluRay.x264.[...
Subtitles in .srt format are the most widely compatible. Match the subtitle file name to your video