Explanation

Box 1: Create a custom connector
A custom connector is a wrapper around a REST API (Logic Apps also supports SOAP APIs) that allows Logic Apps, Power Automate, or Power Apps to communicate with that REST or SOAP API.
Box 2: Use an AppSource connector
You can only retrieve the Customer, UnifiedActivity, and Segments entities through the Power Apps connector. Other entities are shown because the underlying connector supports them through triggers in Power Automate.
Scenario: Customer information is stored in the Accounts entity.
Box 3: Use a native application function
You must produce a report that details the number of registrations for a day and send the report as a PDF to the management team.
Reference:
https://docs.microsoft.com/en-us/connectors/custom-connectors/
https://docs.microsoft.com/en-us/dynamics365/customer-insights/audience-insights/export-power-apps