The macchiato is so often regarded, and indeed made as, a cappucino in miniature. While this is certainly a noble ambition, it is not the intent: one adds the frothed milk to the top of the macchiato as a slight sweetener (the heat breaks the milk-sugars down slightly) that takes the harsher edge off of the espresso, which is why this is such an excellent espresso drink for a beginner.
To correctly construct the macchiato, you will need, in addition to the usual acoutrements, an extra glass or beaker in which to froth the milk. Froth the small amount of milk required first, then extract your espresso as normal. Now, carefully spoon as much froth as is required onto the top of the espresso, being sure that no liquid milk seeps in as this will colour the espresso and be the beginnings of a miniature cappucino: the aim is perfect separation, two defined layers that combine on drinking.