Hi. Posting a story is very simple. We have it stepped out here, complete with screenshots.
There are a couple of important things to remember.
You have to be logged in using the upper right corner login fields only. The center login fields ONLY work at activation. If you use them after that, they will cause an error and you won't be able to post.
If you use Internet Explorer 10, it has a built-in default that causes a problem. We have a way around it, explained here, also with screenshots.
We have a great deal of useful information in our FAQ section. Feel free to explore that, and it might have the answers you need.