Pop up text boxes

I'm recreating an interactive activity that was developed for my client.  They want it to be exactly the same, so I have to add the same features that were used in the original version.  The original version has text that you can click on (a hyperlink) and a separate text/caption box pops with additional information about the topic. How do I add these pop up text boxes in h5p?  I can't seem to figure it out. I'm creating the interactive activities to be used in Canvas, so I'm creating directly at h5p.org.