Once logged in:
(1) Click "Submit an Ad"
(2) Complete the form and click send
(3) Follow the link on the next page to pay via Paypal. If you do not pay now, you may have to repeat all the steps later. The fee is $50.
(4) Email the president and notify him/her that you have purchased an ad. The president will approve your ad as soon as possible. You can find the email here.