Go to the article or PDF you want included in the slideshow.
Click "edit" & scroll down the page to the "featured image" box on the right-hand side.
If you're using extraction, a featured image may already be set. You can click "remove image" to completely remove the featured image or click on the image to change the current featured image to something else.
If no featured image is set, click "Set featured image" to select or upload a new image.
Once your new image has uploaded, or you've chosen a new image, make sure to click it, which will outline the image in blue & add a check mark to it.
Then click "set featured image" below.
You can also crop the image specifically for the slider by selecting "Post Thumbnail Editor".
Make sure the story's checked category matches the category you are using in the slider widget.
If you are posting a new story, click "Publish".
If you are updating a published story, make sure to click "Update".