Dear Susan,
could you please point me to the exact page where you want to display the Recent Posts Slider?
Regarding your second question: the “summary” option works in a different way in WordPress. I suspect the so-called “more link” is what you need: you can show just a part of each post’s content on the blog page by inserting “more” tags into post contents in the place where you want the excerpt to end. In WordPress, you need to insert a special tag into the post content to tell the blog page to display only the content above the tag. In the visual edit mode, use the “Inset more tag” button on the panel above the content; in the HTML mode, the button says “more”; or – you can simply write it by hand (see the links below on how it should look like). You can find additional information on using the “more” tag on the WordPress.org official website, here and here.
Best,
Andrew | Satori Studio