Before you add a new slide, please upload the image for the slide. You MUST upload an image that's 851x314 (for the full width slideshow) or 1200x720 (for the half width slideshow). Those images can be uploaded by New > _ALL > Images > Cover 851x314 and New > _ALL > Images > Feature 1200x720 respectively.
On the left side of the screen, navigate to [your site]/index
Click on the lego block in the upper left corner of your slideshow. Click the link that pops up. Click Edit at the top of the screen.
Fill in the Title field. That will show up above your slideshow.
Select a Speed. This is the number is seconds between slide transitions.
To add a new slide, click any + button. To remove a slide, click the - button on the slide that you want to remove. To reorder the slides, click the arrow buttons.
To change the image on a slide, click the image icon beside the Image field, click Browse, click on the image that you want to use, and click Confirm.
To link the slide to a page within Cascade, click on the page icon beside the Page field, click Browse, click on the page that you want to use, and click Confirm.