Generally its about 30 days from the mating to the laying. There are exceptions due to when in her cycle she is mated, etc.
Once she starts digging, the female may dig several test holes over a period of a few days but should decide on one and dig it until she is satisfied. You should not let the female see you watching her when she is digging because it will make her abandon the hole thinking its not a safe place to lay the eggs. If this happens often enough, it can lead to eggbinding and death.
Once she has dug the hole to her satisfaction, she should turn around butt down and lay the eggs. This often happens in the evening. She may sleep in the hole overnight. She should then fill the hole in and tamp it down and return to the branches, hungry and thirsty and often exhausted.