Go to your User Control Panel (User CP) and go down the menu listings on the left hand side until you find where it says "Chapter memberships" or something of the like. Then just click on that...and go through the list and find the Iowa chapter and click that you would like to be a member. Then, as soon as Roger accepts, you're a member of the Iowa chapter. Took me a couple seconds to remember how I had joined the High Plains in the first place!

Nice ^_^