Unread posts are marked in various places with a red square, which contains the number of unread posts:
In the forum overview https://community.orgadata.com/forum/ the subforum of the unread post is marked.
On the right side in the drop-down menu "Forum" the subitem "Unread posts" appears. Clicking on the menu item will take you to a separate area where all unread posts are listed.
The bell icon for notifications in the upper right corner will be highlighted:
Basically, all news are displayed on the dashboard https://community.orgadata.com/dashboard/.
Some of these options are only available if you have subscribed to the respective subforum or thread.