If when trying to edit your video subtitles the download is opening a new browser tab instead of saving the file to your computer, here’s a quick workaround.
For help getting to this point, click here.
To manually save your VTT file:
When the new tab opens showing the transcript, right-click (or double-tap on a laptop trackpad) anywhere on the page and click Save As
Rename the file if needed, make sure it’s saving as a .vtt file, then hit Save.
You can now upload and edit this file as usual.