Step 1: To edit text, double click on the caption chunk you want to edit
Step 2: Change the look of your captions by clicking STYLE
Step 3: To edit the timing of the caption, click and type in the times to the left of the caption you'd like to "move"
Please know that while you can adjust these times easily, you won't be able to "overlap" a caption with the one before or after it. If you'd like to have more than one showing at a time, consider adding a text box.
Step 4: To add a caption chunk, hover over the caption that will precede the new text and click the + icon
Step 5: To delete a caption chunk, click the trash icon
Step 6: To preview the audio of a particular caption chunk, click the play icon
For more info on changing the style of your captions: How To Style Your Captions