As Rob said, you have started a thread here, so you are part way there. A thread is a new conversation, a post is the individual replies on each thread.
See for a link which tries to help you get started.
http://www.orchidboard.com/community...u-started.html
Tags are optional. You don't need to use them. So just ignore them if you don't no what to do with them.
Tags are really just to help searching later. So you might put a tag of Dendrobium and later someone may want to search for all posts with a tag of Dendrobium. However I don't think most people use the tags at all, and you don't have to put any on your post.
If you are still getting stuck drop me a Personal Message or PM. There is a link in my signature to do that.