You will find the bus-station at the outside of the Medina. You need 10 min on foot from the Bab Doukala. From every place in Essaouira with a "Petit Taxi" (5 Dhs).
Near the bus-stop you will also fin a post office, teleboutiques, a little market of fruits and vegetables.
At the bistro you can buy the whole night something to eat or to buy.
Attention: Around the bus-station there are a lot of touts, which offers a nice and cheap hotel or apartment. They take a commission for a new guest. Please do not follow this offers, even if they say it is closed. A "Petit Taxi" will drives you directly to your hotel.