You can find general guidance for exporting data elsewhere.
6.7.1 Exporting Subrip
Subrip files look like this. Caption text may be more than one line long; the blank line is used to signal the end of the caption.
1 00:00:00,000 --> 00:00:15,365 Start of video. 2 00:00:15,366 --> 00:00:17,432 Puts down toy. 3 00:00:17,433 --> 00:00:25,632 Picks up toy again.
Note that the format is essentially 1000fps, and that commas are used to separate seconds from frames, not periods.
Once you have a Subrip file, you can use it to upload captions to YouTube. Learn how here.