Go to the forum topic of your choice, say Deer Hunting (this one). At the top left hand side above the threads are two buttons just like the one you used post this question. Except they will say New Post and New Poll. Click on the one that says New Post and then make your thread. Don't forget to add a topic. I don't think it will post it if you don't. It's sort of idiot proof in that area.

Good luck.