How do you cook in World of Warcraft?

You have to find a trainer first - a cook - who will train you just like for fishing or first aid. Then, as you travel, buy recipes from the cooks and innkeepers. You need a fire for most recipes, and you learn how to build a fire from the first trainer. Then, just gather your ingredients (meats, fish, flour, etc) and build a fire and start cooking.

The best way to level up at first? Buy enough flour and spices to make 30 spice breads and just stand there making them until you hit the next level.