To create a new page, go to the top left corner and click “Nescio Mature Runescape clan.” This will take you to the dashboard. On the right side of the dashboard you can quickly create new pages. Save the draft. The click the link that is created. Hit publish and check out your new post on the forum.
On the left side you will see a list of recently published pages.
For more specific instructions on how to use the forum, see the Manuals Mordy created listed at the top of the forum page.