Open the video in the editor.
On the left-hand side of the screen, click on the Captions tab
Click inside the box that says Enter a caption and you will be able to begin typing along with the video
To edit or delete the caption, hover over the appropriate caption and click the three dots where the Edit and Delete buttons will appear
If you choose to edit the caption, the following screen will appear. You can edit the time and caption from this screen
Once you have added all the captions you want, click the Apply button in the top right-hand corner to show them to your viewers