Hi solarblast,
to the forum.
You can respond to an individual directly by clicking the "quote" button, which will put their post in a quote block to which you can reply. It doesn't create a new branch, however, it's a straight thread on these forums.
You can contact individual posters by clicking on their username and sending them a private message.
I hope you find what you're looking for and i'm sure you'll love coming back to Australia for astronomy!