This is the easiest thing in the world. I like using my dehydrator set to 115 degrees. If you want you can use a thermos, just put your warm milk in and presto overnight you have yogurt. Also, you can put your milk in jars, wrap them in towels and put them in a cooler or your oven, or you can use your crockpot. Just Google it there are lots of suggestions for making yogurt.
What I do:1 gal Raw Milk 4-6 TBs Plain Yogurt, either your own or store-bought Heat the Milk on the stove to 180 degrees and let cool back down to 115 degrees. You can make yogurt without heating but it will not be as thick in my experience. After heating the milk I like to put it into 4 quart jars to cool to 115. After cooling add 1-2 TBs yogurt to each jar. This is your starter to make yummy yogurt. It can be plain yogurt you purchase or some of your own homemade yogurt. Just make sure it’s not too old so it still has living probiotics in it. Place jars in dehydrator for 10-12 hours on 115 degrees, Or use the other methods mentioned above, they all work. Serve with raw honey, soaked pecans, and frozen blueberries. YUM! Enjoy!