You will need the WiFi Plus+ module enabled inside the back office as denoted by a green checkmark on your Feature Dashboard.  If this module is not enabled, tap the icon and submit a request to enable this feature. 

Typically upon installation, the webpage that redirects users who connect to your guest WiFi network is set to https://google.com by default. However, you may want to send guests to a different page after they successfully connect to WiFi. This page could be your business website, Facebook page, ESPN.com or other online landing page of your choosing. Click or tap SETTINGS> WiFi Settings and scroll to the field Redirect Landing Page.  Adjust the URL as desired and click Save to submit changes, Your redirect URL landing page will be instantly updated after changes propagate to your access point(s).