(Creating as a new linked topic thread, in the Meta category, because this is the category where forum function is discussed.)
I must move on average, 10 topic threads to their proper category each day. It is relatively easy with the Discourse forum engine, as all posts are basically in one database, and a category is really just a property setting, for which topic list to display the thread on.
So basically, you’ll eventually learn where to properly post, by using the Categories listing page, and reading each category’s “About” pinned topic that @jody created when he first opened the forum category.
But when you make a mistake, it’s easy for one of the forum sages, admins or moderators, to quickly move the topic thread to the correct category.
Actually, anyone who is a “Top Contributor” can change the topic of a thread - or even rewrite the title of the thread. It includes forum sages, admins, and moderators, but even more of us here have this authority!
My very first post was apparently made in the wrong category (don’t remember which). I was somewhat puzzled when I found it had been moved by this @tt_su character, but I also remember feeling like I had done something wrong in spite of researching what I thought was an appropriate category. Although ThomThom was gracious in offering to help, there was no explanation given as to why my post was moved and it made me feel like I had screwed up somehow (which I had, of course).
Personally, I think it’s okay (even preferred for clarity’s sake) to move stuff as long as the user is included in the explanation that would follow as a reply to the last entry.