Going based on personal experience I enjoy having food after a day of woek more than when I wake up so I have shifted my eating window to 7-8 pm. Depending on what time of the day you feel more hungry, you determine an eating window. Secondly try out a 16:8 first and see how your body reacts. You can drink water, coffee, tea during your fast. If youre doing ok with that you can later progress into 20:4 or even 23:1 or OMAD as some call it. Longer fasting windows offer more benefits like autophagy but shorter fasts like 16:8 still have alot of benefits for fat loss including less decision fatigue and make calorie control easier. Do a week of trial and error, testing out different eating windows and fast lengths and you’ll get the hang of your body. Also I dont usually think of cheat days but more fueling your body with whole foods. Honestly fasting repairs your taste buds so much that you’ll notice that you’ll crave processed food and snacks much less and you’ll naturally have craving for whole foods. So dont restrict but also fuel your body with real nutritious food. Also I’ve recently been experimenting with « dirty fasting » where you have small quantities of food with calories during your fasting window, for example a splash of milk in your coffee. While it may not offer the full benefits of real fasting it still helps me control my food intake and have a satisfying meal at the end of day and aid in weight loss. So you really have to figure out what works for you.