As account owner, you can set the opening hours by navigating to Account settings at the top right of the screen and then to Opening hours.
You can then specify your opening hours in the middle section of the page. Empty fields indicate your place is closed that day.
Tip: You can also deviate from the norm on any given day. To do this, go to the desired day and select write note or edit opening hours. You can find out more about special opening hours here.