Storyline Lightbox Slides don't stay on a slide

Hello,

I have lightbox slides that are set up to open when pressing a button. There are several buttons on one side. However, the lightbox slide is moving to the next slide without closing. How can I remove this timing so the lightbox slide stay open until someone presses close? I only want each slide to appear when the button is pressed for the individual slide to give a person enough time to read through the text. 

thanks,

Rachel