How can I put a banner on the forums?

Really, this really has been bugging me for a while ^^

You have to buy one of these from the Cash shop or user shop [item=billboard (10k)][item=billboard (50k)][item=billboard (100k)]

Then you submit your ad, and when it's approved it will appear above the forums :)

Thanks!! I don't think I could ever figure it out dumbness