To add subtitles go to the subtitle upload tab located to the left-hand side of the editor, as seen below:

This will open the subtitle upload area:

Here, you can drag and drop your subtitle .vtt file or click to upload it. If the file is the correct length for your video, the player will automatically line it up with your video.

You can check that your VTT file conforms to the correct standards here.

If you do not have the file in .vtt format, please contact your account manager, who can advise on how best to convert to this format.