Why can’t I access a forum?
Some forums may be limited to certain users or groups. To view, read, post, etc. you may need special authorization which only the forum moderator and board administrator can grant, so you should contact them.

How do I post a topic in a forum?

Easy -- click the relevant button on either the forum or topic screens. You may need to register before you can post a message. The facilities available to you are listed at the bottom of the forum and topic screens (the You can post new topics, You can vote in polls, etc. list)