Fortunately, I got an email before you deleted your comment. The additional plugin use was fairly inconsequential to the question. (Or I assumed so in my answer given)
In short, you can use a repeater to attach multiple files. If you need additional data on those files you can put those additional fields in the repeater.
In the example from jaro, they only needed 1 video, but multiple subtitle files which each needed their own additional data (what language they were)
If you happened to need multiple videos, and each of those needed multiple subtitle files with additional data, you could just nest the repeaters.
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