Preheating is necessary for the Adaptive Preset cook programs and recipes that are not part of June's Food ID list. Please preheat the June Oven as you would a regular oven first if you plan on using an Adaptive Preset cook program or your recipe calls for it. The timer and oven is set to start cooking for Preset cook programs and recipes after preheating. At this time, you can place the food in the June Oven while it is preheating without opening the door to start the timer. Simply tap the touchscreen to pull up the menu, and click on 'Start Cooking Now' (or whatever kind of cooking you're doing). However, the timer is in place to make sure your food comes out perfect by placing the food in the June Oven after preheating.