In the block "Once a day" there is some simple hours filter, so you can define particular minute of the day at which the block would pass once.
For that "opening of new candle" part, just use "Once per bar" - https://fxdreema.com/demo/mt4-once-per-bar
What is high and what is low... there is stuff in the "Condition" block. If it's something more fancy, there are other blocks like "Bulls in a row" or even "Single candle template"