Basically I just got a little pint of whole milk and a very small yogurt from the store. Boiled the milk slowly, so it doesn't scorch on the bottom. Once it boils, pour it in an oven-proof bowl and put in 2 Tbsp of the yogurt. Mix that up (with a whisk if you have one, or just a fork) and put it in the oven on low - like either warm or maybe 50 degrees C.
Then leave it as long as you can - if it's during the day, 8 hours or so. I was doing it at night so I turned off the oven after an hour and just left it overnight. Don't move the bowl around or it won't set firmly.
That's it!