How Do I Engage on IH?

I'm a long-time IH podcast listener and a recent subscriber to Plus.

I am still slightly bewildered about how one engages on IH (and suspect many newcomers would feel a friction around initial engagement).

For instance, I know I can "Submit a Post" but it's unclear whether that post will show up as an "article" in IH or more like a "build in public update" or as a "feedback".

The default IH landing page looks very "article-centric" with no obvious way to focus on "build in public" posting so I'm then hesitant about trying to post.

Am I meant to join groups and then a post will be shunted to those groups?

If so, that's also slightly confusing as, without knowledge, "groups" seem like a community object (like threads, say) as opposed to canonical sections of the website (i.e. like "Build in Public" or IH articles).

Writing this post is helping me "rubber duck" and figure it out. But I suspect there are ways to make engagement options more self-evident from the start