FortiInsight monitors endpoint activity in the form of events. It provides automated inspection and alerts against these events in the form of policy and Augmented intelligence (AI) based inspection.
Article Id 197163
This article explain the registration and Activation steps to follow when first purchase FIN (FortiInsight) or if migrating from Zonefox to FIN.

If Zonefox customer:

1) Uninstall Zonefox agent from endpoints - this is optional, it is possible to leave it along with FIN agent however we recommend uninstalling.
2) Register the FortiInsight (FIN) in the support service website
3) Activate the FIN product via the registration code sent to the customer account. 
4) Test registration/activation by accessing the portal URL provided after activation; example: https://<serial_number>
5) Install FIN in endpoints (download the latest agent file from the portal).
6) After endpoint agent is installed test connection by enter the URL https://<serial_number> in web browser, a confirmation connection JSON message will be sent.