Click on the "Settings" tab in the left menu.

Click on the "Rules" option in the bar on the top menu of the page that opens.

Select "Workweek Plans" from the window that opens.

On the page that opens, click the three dots (...) icon next to the calendar you want to make changes and select the "Edit" button.

Specify and edit the name of the calendar, working days, time interval, and lunch break in the relevant fields and click the "Save" button.