Go to Dashboard > Session Control. In the header, click on your email, and click My Profile . Please ensure you have selected your timezone as schedule shown on the listing is based on your timezone.
Click on Working Hours tab. You can set your working hours here. If you want to set the same schedule for the entire week, simply set it for Monday and click on the Apply to All Days button and the Monday schedule will be copied to the other days.
Click Save Changes when you're done.