Open the selected document in the tab marked with a question mark (tile on the left side). Hover the cursor over the field in the ABSENCES column until a plus icon appears, then click it. If the schedule is in edit mode, a message will appear—confirm it. Select the appropriate absence from the displayed list and confirm by clicking OK. Enter the absence details, such as date, hours, comment, or attachment, and then confirm the entered data. The absence will be added to the schedule.

For more information, see the article: Absence planning.