A litre of milk set with a quarter of a rennet tablet, drained and pressed into a round. Three ingredients, and the milk has to be ordinary pasteurised rather than long-life or it will not set.
Use ordinary pasteurised milk, not UHT. This is the single reason most homemade cheese fails and the recipe never mentions it. Long-life milk has been heated so far that its proteins can no longer form a curd, and rennet added to it produces nothing at all. In Colombia the recipe says leche en bolsa, bagged milk, because that is the everyday pasteurised kind; the point is the pasteurisation, not the bag. Lukewarm, not hot. Rennet works at around body temperature and is destroyed by heat, which is why the first step takes the pot off the stove before the tablet goes in. If the milk is too hot to hold a finger in comfortably, let it cool. A quarter of a tablet per litre, which the recipe's own note confirms. More does not set it faster or firmer: it makes the curd tough and can leave a bitter taste. How long you drain it decides what you get. A short drain gives a soft, wet cheese; longer and heavier pressing gives something firmer that slices. Either way it is a fresh cheese and it keeps only a few days.