To order food or drinks at Joe's Oyster Bar you need to order from a waiter. Waiters will come to your table to get your order.
You can also always find a waiter in front of the bar in the main bar area. The waiter's are the guys with the white t-shirts that say "Working at Joe's" on the back.
The bartenders in the main bar area don't normally take drink orders. It is highly recommended that you get to know your waiter and tip him well! Then he will look after you!