Add a Caption To an Existing Slide

## Can you think of a better caption?
Each slide can have more than one caption. Check out the current slide show and add a caption (or two).
If you need help, check out the Appendix in the training manual.

Start by opening the repository's current slide show and reviewing the Appendix in the training manual for caption guidance. Add one or two captions to an existing slide, then verify the slide show displays them and that the wording fits the slide.

Written by the indexing model from the issue text.