It would help to have more information.
- Do you already have the script?
- Do you need 1 and 2 line captions (example) or 2-line rolling caption, like US closed captions (example)?
Easiest way is to simply create a HTML template that will accept the captions and a client to control them. You could control them from the CasparCG Client by creating an item for each caption and using either STOP or NEXT to clear them when you don’t want them displayed anymore.
I have a system for this, but it’s part of a larger one so won’t work for you (it’s used for live captioning and subtitling music [like operas] etc). A quick search on GitHub came up with this (don’t know anything about it) https://github.com/BSStudio/caspar-cc
Perhaps vimlesh1975’s Simple Video Playout can do this: Simple Video Playout
If you don’t have a script beforehand, Web Captioner might be of interest to you: https://webcaptioner.com/