To add working hours you go to Tools > Intervals
To add a new intervall press the plus sign in the lower right corner
Add a name and a description
To edit your new interval press the three dots on the right and then press "Edit Interval"
Then press "Intervals"
To add a new sub-interval press the plus sign
Add a name and then change the following:
Type = Custom
FROM = When the office should open (when you add a time here the TO field will appear)
TO = When the office should close
FROM = The first working day in the week for your company.
TO = The last working day in the week for your company.
In the example below the working hours are 08:00-17:00 Monday - Friday.
It will be closed all day Saturday and Sunday
FOR A WORKING HOUR INTERVAL YOU SHOULD NOT ADD "MONTH DAYS" OR "MONTHS"