You can post THREADS under the FORUMS section.
'You can post ARTICLES under the ARTICLES section.
You are probably looking to start a THREAD.
(If I am guessing right
Go to FORUMS
When you click on FORUMS scroll through the different sections
When you spot a section that you think your POST will fit in click on the TITLE (bold blue lettering) in that section.
Once you click the title it will take you to a list of a whole bunch of different THREADS.
At the top of this list you will see a blue button POST NEW THREAD.