Could you please clarify which of these you're interested in so I can provide the right steps?

:srt or .ass subtitle file that matches that specific video release ( WEBRip.x264-ION10 )? Troubleshooting & Setup :

If you're just looking for general tips, you can find helpful subtitling do's and don'ts from or troubleshooting steps from Crunchyroll for web playback issues. Subtitling tips: Do's and don'ts - LanguageWire

Depending on what you're trying to do, this could mean a couple of different things: