You can edit the days and times when you're available to take appointments right on the Schedule tab. First, go to the Schedule tab and check only the staff member(s) whose available hours you want to update. Then, click the 'Edit hours' button, choose to either make hours available or unavailable, and adjust the 'Recurs' setting as needed. Then highlight the hours you want to update on the calendar by clicking and dragging until you have the hours you want. Then save your changes.
Available time is displayed as 'white' on your schedule and unavailable time is displayed as 'gray'. So if you have available (white) time that you want to edit to unavailable, you must follow the above instructions using the "Unavailable" button. And if you have unavailable (gray) hours you want to edit to available, you must follow the instructions using the "Available" button. You may need to make several updates to reflect all the changes you need. Please note that after the initial setup, edits to business hours under Setup > Company will not update the hours you are available for clients to schedule appointments.