1. Open an account or sign up with your facebook account
3. Arrange them.
4. Add effects (or not)
7. Share or embed, you can get your embed code or share it on the following social networks: facebook, twitter, stumbleupon, google+ or pinterest. Unfortunately, they can’t be embedded on WordPress.com.
It also offers the possibility of having your slide.ly publish or private.
Under this link you have a quick example I did for this post. It took me no more than 2 minutes.