You can set workday and holidays in the properties window of scheduled project. For example, if you set Monday to Friday as workdays, and Saturday and Sunday as holidays, task duration will skip holidays during auto-adjustment.

In real-world corporate environment, however, there are public holidays and overtime that would affect task durations, leading to misunderstanding and delay. In response, go to the "Exception" settings in the Workday section of Project info, and set public holidays and overtime on the work calendar.

Note:

1. Only project leader and administrator are allowed to set workday and exception.
2. Changing project workday and exception will also change the start times and deadlines of its tasks on the principle that duration stays the same.
3. For instance, a public holiday is added as a workday exception to the project, as shown below:
    

The corresponding task start time and deadline will also be automatically adjusted due to the addition of exception workdays and exception holidays!

Add workday exception

1. When creating a scheduled project, click "Advanced" > "Exception" to open "Workday exception settings" dialogue box.
   
    
2. Click "Add" and select the date to add as exception in the pop-up calendar. The system will automatically set the selected date as exception holiday or exception workday, and the Exception list will include all added exceptions. Still confused? The rule is simple: a workday will turn into a holiday after adding, and vice versa. As shown in the following picture, when September 13 is selected (Mid-Autumn Festival holiday), it becomes a holiday exception.
   
    
3. Click "OK" to go back to "Advanced" dialogue box.
4. While in the "New Project" window, fill out required information and click "OK". The exception settings will be uploaded to the server.
   

Note:

Workday exception is based on workday settings. If you go back to "Advanced" page and adjust the workday settings, existing exceptions will be adjusted as well. Based on the latest workday settings, the system will filter out added exceptions which are deemed invalid. For example, if you go to "Advanced" page and deselect Monday as workday, since September 24 is already a holiday which does not need to be added as exception, it will be removed from the exception list.

Delete workday exception

1. Project leader or administrator opens the "Project info" dialogue box and clicks "Exception".
   
    
2. In the "Workday exception settings" dialogue box, select an item from the Exception list and click "Delete".
   
    
3. Click "OK" to go back to the "Project info" dialogue box, and then click "OK" to save the changes.