How do I cook meals?

According to this site, you have to:

Approach a metal bowl. Light a fire underneath it if necessary. Press + to enter your inventory screen, and choose up to five ingredients to hold. Approach the bowl and, when prompted, press A to cook. It’s that simple.

Additional information is found on the site in question, including cooking elixirs and what types of foods you can cook.

There are several methods to prepare your ingredients:

• Cooking: Gather your ingredients and walk up to a cook pot on a lit fire. It will prompt you to put them in and cook the food/elixir. This is the only way to combine ingredients to make food.
• Roasting: Any high temperature source will do. Just take the stuff you want to roast and put it on the ground next to the temperature source. You can use a fire, a torch in your hand or even the super-heated air of Death Mountain! (Any meat or fruit dropped in Death Mountain cooks in a second in the hot zone).
• Freezing: Put your food next to something super cold (cold air or cold water) and you can freeze your food. Northwestern Hyrule is very cold, any meat dropped by animals there freezes in seconds. Unlike roasted foods, which have no special effects, frozen food offers some protection against the heat.
• Boiling: Put your food into some hot water, such as a hot spring, to boil it. Soaking in a hot spring is also great for restoring HP.

Another method of cooking is by using a Fire or a hot location, such as Death Mountain. Simply drop the item you wish to cook near the fire or on Death Mountain, and it will cook after a short time.