Media subtitles page allows you to manage subtitles for a given video. Here, you can upload or create new subtitles using the Subtitles Editor or by transcribing the audio. Once subtitles are created it is possible to automatically translate them into another language. Make sure they are then reviewed by a human as translations might not be 100% accurate. 

Moderation of subtitles
All subtitles must be approved in Console before they are visible to viewers.
By default all subtitles will be hidden, so that they can be edited and corrected before visible. 
When the subtitle is ready for publishing, press the eye icon to change moderation to visible to make it available in the video player.