You are looking to add a button to your tour with a link that opens the phone app and lets people call you straight away.
Add an “Info” hotspot and choose from the “Call to action” icons or upload your own:
Remove the camera icon:
Click the image to add a new icon
Click “browse” to select an image or upload a new one
Resize the image to choice
Now add a “text” hotspot
Put the text hotspot over or just under your call to action text:
Delete the default text and add only dots (……………………..) then highlight the dots and click on the “link” icon.
In the pop up, choose “other” as link:
In the URL, put the words “tel:” and your phone number (including country code is best)
Click on the tab “target” and set to “self” (so it does not open in a new tab)
Now you want to make sure you don’t see the dots:
Set the “alpha and BG Alpha both to “0” (zero) to make the text transparent
Now you don’t see the text unless you hover over it with your mouse. And on mobile it is just a fine line under your CTA text.