How Do I Natural Release at the End of Pressure Cooking

When a recipe tells you to Natural Release after pressure cooking, that means you do nothing. The valve stays in the sealed position and over time, the pot will cool down enough that there isn't any pressure left. Pressure is created by the steam trapped in the pot and as the contents of the pot cool, the steam returns to a liquid form and pressure reduces in the pot. 

You will not hear or see anything while natural releasing. 

Sometimes, a recipe will tell you to natural release for a period of time, let's say 10 minutes. Use the timer that is counting up while the keep warm function is on and allow the 10 minutes to pass, then you turn the pressure release valve to vent and release the remaining steam until the pin in the back depresses and it's safe to open the lid. 

You don't have to worry about the keep warm function being on during natural pressure release, it doesn't prevent the contents of the pot from cooling down and it doesn't prolong the pressure release. Think of the keep warm as a thermostat that is set to around 150-160℉, if the contents of the pot are 200℉, the keep warm doesn't do a thing. It's only when the contents of the pot reach temperatures of 160℉ or lower that it would kick on to keep the food at a safe temperature so bacteria doesn't grow. These numbers are used for demonstration purposes only, I have not been able to find out what the temperature setting of keep warm is yet, but since food has to be kept at 140℉ or above for safety, I'm assuming it's around 150℉.