Place the movie file and the subtitle file in the same folder.
When searching for subtitles, you must match the "release name" of your video file to ensure the timing is correct. Because BluRay releases usually have the same frame rate ( 23.97623.976 subtitle The.Addams.Family.1991.1080p.720p.BluR...
Open the movie in your player (VLC, MPC-HC, or PotPlayer), and it should load automatically. Open your video file in your media player. Place the movie file and the subtitle file
Rename the subtitle file to match the movie file exactly (except for the extension). Example: The.Addams.Family.1991.1080p.BluRay.mp4 The.Addams.Family.1991.1080p.BluRay.srt subtitle The.Addams.Family.1991.1080p.720p.BluR...
OpenSubtitles: A massive database where you can filter by language and resolution.