The recipe shows the quantities per person. Increase the recipe as needed depending on how many people you're making hot chocolate for. Keep in mind that this is pretty rich!
Heat the milk to steaming either in the microwave or on the stove.
Take off the heat and whisk in the chocolate until melted. For a slightly thicker hot chocolate, add more chocolate or let simmer for a couple of minutes.
Enjoy with marshmallows or some whipped cream!