Add the powdered milk and stir until completely combined.
Heat on saute function to 180 degree F.
Take liner out and place on a trivet.
Let mixture cool to 110 degrees F.
Add the yogurt culture.
Return the liner to the instant pot.
Cover with the lid set to venting or with a glass lid. I remove the gasket so I won't get any odors from other foods in the yogurt as it ferments.
Hit "yogurt" function. You can hit the yogurt button until you get the desired time. I set mine to 24 hours. You want it to culture for at least 6 hours.
After it ferments, you can put the mixture in an airtight container and move to the fridge or strain it for a thicker yogurt.
To strain, put a colander over a bowl and line with a tea towel.
Pour the yogurt over the towel and allow to strain for 30 minutes to an hour for a thicker yogurt.
Notes
Store yogurt in an airtight container in the fridge for 7-10 days.