How to use Dynamics Notifications(Mention, Reply..)

Dynamics Notifications(Mention, Reply…) do not work.
When I register posts or use mention, notications do not work.

So I saw the discourse code. But, I couldn’t find the part that creates notification after registering post.
Do I have anything to do in admin settings?

I downloaded and installed from github(Discourse version 2.1.3)
(GitHub - discourse/discourse: A platform for community discussion. Free, open, simple.)