The easiest way to heat milk is in the microwave, but you’ll have to keep an eye on it. One cup (250 mL) of milk should reach room temperature within 45 seconds and boil within two and a half minutes. Stir it every 15 seconds to keep it from boiling over. You can also try setting your microwave to 70 percent power for a slower boil. You should still stir the milk every 15 seconds. When boiling milk on the stovetop, use a deep pot so the milk has room to bubble and crawl up the sides. If you’re making a sauce or a glass of warm milk, set the heat to medium. To keep the milk from boiling over, don’t turn your back on it and stir it every few minutes. Lower the heat when the milk starts to boil to avoid scorching it. Milk boils over when a layer of protein and fat forms at the top and prevents steam below from escaping as it heats. Eventually, the steam breaks through violently and the milk boils over the sides of the pot. Keeping a long-handled spoon gives the steam a way out before too much pressure builds. You should still put the spoon to use every few minutes and stir the milk to release steam. If you’re making cheese or yogurt, you should heat milk by one degree per minute. Heat it at low to medium-low for 30 to 40 minutes and stir it every few minutes. When you see tiny bubbles and steam, the milk has met its boiling point of 180 degrees Fahrenheit (82 degrees Celsius). If your stove runs hot and you can’t boil milk slowly enough directly over a flame, you could use the double boiler method.

TL;DR in Indonesian:
Panaskan di dalam microwave. Didihkan susu di atas kompor pada panci besar dan dalam. Letakkan spatula bergagang panjang di dalam panci. Panaskan susu untuk kultur secara perlahan.