The first step to providing your clan with their very own forums is to decide on where to host it.
Free Forum hosts include services such as InvisionFree, IPBFree (for InvisionFree Boards) and FreeForums (phpBB based forums). All services that are free obviously will include some form of advertising.
Chances are, one of your clanmembers might already have access to a server where you can install your own phpBB forums, without advertising. It's at least worth asking before you sign up for a free service or decide to pay by yourself.
All forums will require you to set up some basic things first, in order to make your forums effective for your clan.
First, you will want to create a couple usergroups. By default you will have Guests and Registered Users. The first group to make should be labeled something similar to "Clan Members". The second one should be "Clan Leaders".
You will then assign users to their appropriate group ("Clan Members" or "Leaders" for people with full access). If somebody first registers to your forums they will be in the "Registered Users" group.
Note: ALWAYS keep up-to-date with usergroups. If somebody joins clan they should have access to the clan section, and if somebody leaves he should have his access revoked. NO QUESTIONS ASKED. Letting somebody keep access even if they are not in clan will cause problems, try to avoid it at all cost!
Next, setup three forum categories: "General", "Clan", "Leaders", or similar. Give the appropriate group access when you create them (General for registered users, Clan for Clan Members, and Leaders for Clan Leaders). Then you can set up forums inside those sections, below are some examples:
General: Recruitment, General Talk, Pictures/Media, Trading Section, ...
Clan Members: Clan Chat, Boss Hunting, Screenshots, Problems, Specific Events, ...
Leaders: Leaders only, ...
Adjust the categories as you see fit for your clan.
As clanleader and assistants you should always be on top of your own forums, which means checking them daily and settling any disputes before they escalate. Do not tolerate any illegal activities for everyone's own protection. As clanmembers, please advise your clanleader promptly if you have any troubles with any content on the forums.
It is always recommended for a clan to encourage all members to participate in forums. Especially in Knight Online World, where you might have people from very different time zones in one clan, it keeps the communication between everyone flowing.