You already have hours published
A new account starts on Monday to Friday, 09:00 to 17:00, in your business's timezone. That is so your booking page can offer a real slot on day one — but nobody at your business chose those hours, so the setup checklist keeps asking until you save your own.
Changing them
Open Schedule → Availability. Set a window for each day you work; leave a day empty to mean closed. You can add more than one window a day — a morning block and an evening block, for example.
Overnight work is two windows for now: one that runs to midnight and one that starts at midnight the next day. A single window cannot cross midnight.
You can also block specific dates — a holiday, a family wedding — without changing your weekly pattern.
What families see
Your booking page computes open times from these hours, in your timezone, minus anything already booked. Times are labelled with the zone so a family in another state books the hour you meant.