1. The video must be 1080p
2. Upload the video to
3. Select No, it’s not made for kids option
4. Press Next and then Next again
5. Select the option Unlisted
6. Press Save
7. Depending upon your video, it might take time to auto-generate your subtitles
8. On the left panel, Click Subtitles
9. If you click the down arrow under the video’s languages area, it should show a caption that is already created by youtube for you.
10. You can click Duplicate and Edit to edit the caption
11. You should see the auto-generated caption without the timings
12. Click Assign Timings
13. If you verify the caption is correct, you click save the draft (for later editing) or publish.
14. If you wish you want to create the caption from scratch
    1. You can click Add under the Subtitles
    2. Click Type Manually
    3. You can add text, and its corresponding timing
    4. You can also use the bottom timeline to edit the timings and verify the captions
15. Share your video links.

 

You can also refer to for instruction.