You should start by just using [size] and [color] and [b] to emphasize the name. You should also [center] everything and then add [spoiler] for each individual category.
Like a spoiler for your story, a spoiler for your recruitment, a spoiler for your members and ranks etc.
And the message to your clanmembers should be a reply to the thread, not in the thread itself.
As a reference feel free to use my clanthread or even my fite nite thread and instead of images use text for now