hello Arne,
In WidgetKit menu, go to Slideshows and add some text in the Caption field http://prntscr.com/pi9pqm
you can take this code as a template or just add your own
<div class="slider_caption1">
<h2 class="color_black" color="red">Looking For A WordPress Theme?</h2>
<p class="color_black"> Grab This Theme and Start Making Your Websites.
<a href="" class="btn2 black">Learn more</a>
</div>
let me know if you have any further questions