First thing you need to do is to prepare your mesophilic starter. This is a compound of bacteria that ferment milk at room temp. You can do it by leaving milk at room temp for 24 hrs or by inoculating a little bit of milk with the content of a probiotic drink or a yogurt. It needs to be brought to room temperature well in advance (in the morning) to give a chance to the bacteria to start working. Lactobacillus acidophilus does a great job and you find it in most probiotic drinks and some yogurt but if you want to use professional stuff you can buy a proper starter like this one (it's enough to inoculate 150 liters of milk). If you go for yogurt or some probiotic drink, make sure there is no Bifidobacterium because in my short experience it does not allow the milk to curd. Streptococcus thermophilus and bulgaricus are ok as long as there is lactobacillus acidophilus. So, second thing you need to do is to bring a liter of pasturaised milk to 21°C in the evening and add a couple of spoons of the mesophilic starter you prepared in the morning. Leave everything at room temp and the bacteria will use the lactose in the milk producing lactic acid as a byproduct wich will lower the pH causing the milk to curd (usually between 8 and 12 hrs but could take up to 24). The amazing thing (to me) is that you get a very firm curd without rennet. So it will have probably curded by morning but if you dont have time to do anything, just leave it for when you come back.
Let it rest for an hour.
PS. If you have dogs, they love whey, it is a good although poor source of protein and you should feed it to them.