How would I enable Team Member discussion notification?

Hi,

We are starting the use of Team member application, we expected to have a chat using the discussion field, but when a user only posts a discussion, the Project manager does not receive any notification about the new message.

How would I enable notifications when a discussion is posted?

P.D. We have a proper performance when the activity changes and the Project manager receives the notification to "Review status updates", but when the Team member only posts a discussion the only way to find it is looking into the activity.

Thanks in advance,

Leonardo