If you want to post a new Thread, go to the Forums menu tab at the top of the main page.
Click on that, then scroll down the list of categories and find the one that best suits your question. If you can't find one, go to General topics and post it there.
Once you are in the category, there is a "New Thread" button in the left corner of the page about 1/4 of the way down, but above the various threads in the category.
Click on the "New Thread" button, and a new box appears. Put in a short title for your question, then head to the main message box and type away.