In order to make Bread you first need Wheat which you get by planting Seeds (you can find the seeds in tall grass). Find a piece of grass near water and use a Hoe to reveal the soil then plant your seeds and wait for them to grow. You'll know it's Wheat when it begins to change colour into a murky green/yellow colour. Take out the Wheat and go to your crafting table and select Bread. You'll need 3 pieces of Wheat to make Bread.
Sidenote. Using Bonemeal will speed up the Wheat growing process.
My video shows how to get the Achievement.