The Call to Action button [CTA] allows viewers to take action when viewing the tour which would be viewed as a conversion for a client. In essence, it is what your client wishes to accomplish by having a custom tour.
The CTA is therefore by default tracked conversions for a client. You will notice that is has a check mark in the settings from the right side. You can toggle this off if you do not want to track it as a conversion.
To edit CTA button simply open your tour, go to the edit tab, and then click on the CTA button from the menu on the right.
This button has two actions. It either opens an external URL in a new tab or allows you to embed a page in the main screen. Most of your clients will already have a page set up for conversions. Whether that is a reservations page or an application page. You can choose which action the button will take by opening the CTA settings and changing the button action type to either Iframe to open it in the main tour window or blank for a new tab.
To set the link for your client's current page for conversions simply go to that page, copy the URL and paste it into the button content URL