The Express Kitchen is more than a take out window; it's basically a counter service location. It has its own dedicated seating area (I think it's all outdoors or almost entirely outdoor seating) and is located to the left of the Jazz Kitchen (when facing). You go up to the counter, place your order, pick it up, and then take it to one of the tables or wherever you want to eat. It has it's own menu and, as far as I know (it's been a while since I've been there), you cannot order from the Jazz Kitchen menu at the Express (other than for the items that appear on both menus, like the beignets).