Each person's hours are on their card under Shop settings, People and places: press Edit, then Hours. With more than one place, the hours are set for each place. The diary shades the hours you are shut, so the white space is what customers can book, and a gap between two working stretches shows as a break (lunch unless you name it).
For time away, open the diary, press Add and choose Blocked time. Pick whole days, or a start and an end time; whose time it is (one person, or Everyone when the shop is closed); and what it is for: lunch, coffee, admin, training, personal, travel, or your own words. It can repeat every few days or weeks, and each block can be removed on its own. The booking page stops offering those times straight away.
A holiday is a blocked run of days. Choose Everyone to close the whole shop, or one person to take them off the booking page while the others carry on. Blocking time stops new bookings; look in the diary for anything already booked in those days and move or cancel it yourself.
A login on the Diary only role can block their own time off, and cannot touch anyone else's.