Depends if you are conservative or liberal. As a liberal you click on the specific forum. There will be a tab stating new topic up at the top right of the screen.
If you are conservative, you log into the whitehouse website and ask if it's okay to think for yourself with a new topic. Then, go to the Obamacare website and sign up for health insurance. You will be contacted by the IRS and audited. They will decide to either allow you to post your new topic or imprison you for 5 years. So, be careful what you post