This section is if you have requested captions, if you uploaded your own caption file then you can go back and edit them and upload them as needed.
Once you have requested your captions and they have been processed under the captions tab you see the manage captions option.
Selecting the three dot next to the review and publish tab will open a menu with options to edit, download, replace or delete the caption file.
Once you selected edit you can go through and correct any captions that might be off. This is a good idea since the auto-generated captions are only 85% accurate. Once you have made your corrections select the publish option.
