Hello AnnaLisa,
Instead of category in slider, you want to use page for it. If you are familiar with WordPress codes, you can customize the theme as your need. Its not so easy to provide the ready made code for this issue because you have to do lots of coding and CSS for it.
We are going to release the premium version of this theme within few days. On that theme we include lots of additional features and also the options for selecting page on slider. Would you please wait for few days and go to the premium version of this theme so that it help you to make your site more reliable.
If you have any more query, feel free to ask.
Thank You
Acme Supports