Brass is made of copper and zinc, and although it is often used in a decorative way around cooking utensils, it is rarely the main metal used for pots and pans. Copper and brass make for excellent heat conductors, but if not lined with another metal or coating, they can easily leech copper into food, especially if the food is acidic.
Read the manufacturer's instructions if you have purchased a new pot coated in brass.
Use wooden or silicone coated utensils with pots and pans lined with metal or a non-stick coating to prevent the lining from getting scratched.
Place food in the brass pot or pan prior to heating. Brass pots and pans should not be heated when empty.
Use low to medium low heat after the brass pot or pan is up to temperature. Extreme heat is not needed since the copper in the brass will hold the heat well.
Cook a simple meal in your pot or pan the first time to get an idea of how it handles heat. Sauté some onions and mushrooms or cook an egg to see if there are hot spots or how quickly the pan heats up.
Add granular substances such as salt or sugar after putting other ingredients in the pot or pan, otherwise the salt or sugar can pit the lining.