If you are using OOB page and widgets, setup is already there. You should see cda-site-analytics widget in header, it doesn't specify profile name so analytics will be tracked with default profile. 

If you are adding profile name, make sure the profile name is correct and the profile is active.

Visit the portal with different impersonated users, redirect to some other page so browser buffer is flushed to server side buffer  (or it will be automatically flushed approximately in 5 mins), then wait for approximately 15 mins or more. All the tracked events data is queued (first in browser buffer then in server-side buffer). Once the profile import trigger runs you should see the data.