Override Basic Actions for Activity
Overriding a standard button changes what happens when a user clicks on it.
To launch the Activity Report Visualforce page instead of having a standard Salesforce page, you should override the New, Edit, and View buttons.
To override the Edit button:
-
Go to Setup (1) → Object Manager → Pharma Activity (2) → Buttons, Links and Actions (3).
-
Click Edit (4) next to the Edit label.

The Edit button page opens.
-
In the Override Properties section, next to Salesforce Classic Override, select Visualforce page →
ActivityReport [CTPHARMA__ActivityReport]and click Save.
The Edit button is overridden.
Repeat these steps to override the New and View buttons.