To add captions to a Submission, you must first create an .srt file. For more information on how to create an .srt file, look at this blog post. At ApprenNet, we recommend using Aegisub, but there are many other ways that one can create an .srt file. Once you have your .srt file, follow the steps below:
Navigate to the individual Submission page.
Select the Subtitles button in the top right corner.
Select Choose file.
From your file browser, select your .srt file.
Enter your language code. "en" is English.
Once you've uploaded, your page should refresh and you should be able to select your caption file from the 'CC' option on the video itself.