1. Find a great video on YouTube.com
The video will need to have captions enabled for CaptionCub to work properly. (You can check this by seeing if the "CC" icon is available on the video)
2. Click the down arrow to expand
On the right side of the captions search field, click on the down arrow to expand the tool.
3. Follow the active caption
As you play the video, you'll see the actively synced caption in red.
4. Helpful tips:
You can scroll through the captions to find the spot you're looking for and after around 7 seconds, the active caption will come back into view
To select on specific caption, you can either hover the caption and click the play now button or you can click on the text itself
For long videos (over an hour long), it may take a few seconds for the captions to load
If captions weren't enabled by the content uploader, you won't be able to use the tool. Sad.
If you run into any issues, try refreshing your restarting your browser