Homegade yogurt

Hello to all. I know that some of you already know this recipe but I’m sharing for those who want to know how to make homemade yogurt very simply and without a yogurt maker…
1kg of milk powder
3litres of lukewarm water (not hot)
A pot of plain yogurt (any kind, I used a vanilla flavored one)
Cover and use a container that closes well. Let it sit overnight preferably (or for 8 hours)
Then put the flavor of your choice (for me it’s vanilla) and sweeten to your taste