Generally you should prepare your files to comply with a naming schema Plex can understand. You can do that manually or by using apps like FileBot (though with very crazy file names those apps might have some trouble too).
TV show format
Show Name: ${showTitle} (${showYear}) {tvdb-${showTvdb}}
Season: Season ${seasonNr2}
Episode Name: ${showTitle} (${showYear}) s${seasonNr2}e${episodeNr2} ${episode.title}
Movie format
Folder format: ${title} (${year})
File format ${title} (${year}) {imdb-${imdb}}