Ok, wana start your own forum?
Ill tell you here..
1.) Go to this Free forum host.
2.) Register your own forum & and complete the email code.
3.) Now, Login to your forums ACP (Admin Control Panel)
4.) Cofigurate the board settings to your idea of the forum.
5.) Now add some forums (Try get some giod forums that keep members coming)
6.) Select your forum style.
7.) Get a cool banner and Favicon to go with your forum.
8.) now, logout of your phpbb3 ACP and post on all the topics you made in your ACP.
9.) Advertise your forum On one of these:
10.) enjoy !