Plugin for Book

I posted this question over in the themes category, and I think I should have posted it here. I want to add a picture of a book and a link to buy it at Amazon, just like the one on the www.ads-software.com page (FWordpress for Dummies), except I’d like it to appear over my category listing. I’m using the SimpleX theme and I’ve just started using wordpress, so please use small words and much patience.

You can see the site over at https://www.sevenlions.org (It’s nothing fancy, of course).