The landing page is a web page which serves as the entry point for a website/portal. This helps the network admin to set a module that admin thinks network users will be engaging with the most with.
In MangoApps, network admins can set the default Landing page for all the users directly from the admin portal.

Network admin can select
a. Apply these settings to all existing users and new users – This setting applies to all existing and new users. This is not applicable for Guest users., Or
b. Apply these settings to new users only – Existing network users settings will not be changed. This is not applicable for Guest users

However, individual users in the domain can over-write the Landing Page to one that they wish to have by going to Change My Settings › Landing Page
The users can select a default Landing Page from the drop down and select save.

Here is the video to illustrate the setup of the Landing page from the admin portal.