Forum app in Nextcloud

I am new in using NC, and I would like to know is there maybe forum application (like this), that can be used within Nextcloud.
Also, what is the software that you are using for this forum.

There is no dedicated in Nextcloud forum app, but you can comment on files and have a chat system with the Talk or JSXC apps.

You can also integrate a forum like this one via the Discourse SSO app:

Thank you, I understand this single sign on plugin, and I will try to find some documentation (step by step luckily, or “For Dummies” ) how to install “Discourse” (on same server, I hope) and how to connect it as external application (I am not sure how that is functioning).
If you already have some experience maybe you can point me in right direction (more).
Thanks again.