I've seen a lot of folks join the community recently, so welcome! This is the place to post questions about Hubzilla, or instances, or Federation in general, how to connect to people on Mastodon or other federated platforms, or whether a feature is available and is hidden in the options somewhere (lots of things are hidden in the options somewhere!).
If you haven't posted to a community in Hubzilla before, you just need to go to the Community main page (if you see "Stream Filters" on the left, you can choose "Forums" under that and should be able to find "Tech Talks Community" from there), and then use the "Share" field at the top of the screen to post. :)