make a simple tradingview indicator pine script

I need a indicoator for tradingview where this indiocator basically can calculates the average candle body sizes. I want a have a option to choose from which date to date( certain time of the day everyday/ let’s say candle body average size from 12:00am - 11:59pm but I can choose the time). I think it’s super simple and I can also send u a guide for this indicator how to make it.