The landing page, if configured, is the page where the end-user is redirected to after a successful authentication to the Splash Portal. Usually you will choose the landing page as an Internet public page, external from the Splash Portal.
You can configure a landing page in the Cloud4Wi Dashboard, by accessing the Splash Portal section, clicking the appropriate Splash Portal and then clicking the Settings button.
See the following article for details on this: Setting appearance, languages and public URLs for your Splash Portal