Course members can add Polls and Questions, Articles, Events, and comments to the Course Activity Feed as long as these features have been enabled within the Course.
When you add a Post or Event in a Course, it will have a tag that indicates the name of the Course where that post lives. The tag will also indicate if the Course is private, which means that only Course members will see that Post. As a Host, you can move a Post or Article to and from a Group by editing that Post and adding or removing the Course tag.
In your main Mighty Network Home Feed, you'll see all activity from the Topics and people you follow, along with all activity in the Groups and Courses that you're a part of. Posts that are in Courses will have a tag on them that indicates the Course name and privacy level.
"Pinning" Posts to a Welcome or Featured Section Within a Course
To do this, first make sure you've added the Post, Article, Poll or Question you want to feature to the Course. Then, go to the three dot menu for that activity and choose to add it to "Featured" or "Welcome."