There are many services available on the Internet that allow you to create your own forum, such as Proboards, Forumation and Lefora. These services allow you to host and customize a forum of your own, and different hosts may offer different helpful features for your forum.
Generally, all you need to do to create your own forum is to sign up for a service such as Proboards, Forumation or Lefora. Then you can customize the forum to your desires. Different services offer different types of forums and different levels of customization, so depending on how you want your forum to look, you may wish to shop around.
Once you sign up, you can add different boards and subforums to your forum. The process is usually very simple and straightforward. Most forum hosting websites allow you to completely customize your forum, but this may require some knowledge of CSS or HTML editing.
Many forum hosts are free, but you may need to sign up and pay for a subscription to access professional level features for your forum. Be sure to check the features of the forum host you sign up for so that you make sure you are getting everything you need.