First put the oatmeal and almond milk in a saucepan and heat on low to medium heat. Then slowly increase the temperature, but never to the highest level. Slowly bring the mixture to the boil, stirring constantly, and add cinnamon and sugar or agave syrup to taste.
Possibly put the porridge in the fridge for a moment to cool down.
Cut the mango into small cubes. The best way to do this is to cut along both sides of the mango close to the core and scratch a checkered pattern into the rounded, cut parts of the mango. Turn the peel of the mango inside out by pressing lightly and cut the cubes from the peel.
Finally, put the mango cubes on the porridge and enjoy warm or cold.