The availability of an employee is calculated on the basis of 3 aspects with following priority:
Availability as filled in by the employee himself (in the menu under My schedule - Availability).
The approved leave of the employee. This leave can be requested by the employee himself or filled in by the chief.
The standard working hours of the employee (in the menu under Management - Users).
An overview of 1) the filled in availability and 2) the leave is available in the menu under Schedule - Absence & Availability. But first you need to Filter on 'Show availability'.
While planning, the availability is shown by the dotted lines.
In green you have the default availability, in blue the additional availability.
For more details about the default availability, please read this article.
First of all you should check whether you have checked "show availability" in the view settings.
Click on the eye in the side bar.
In the week view this is show as followed:
The default availability is in green:
The extra availability is in blue:
In the day view this is show as followed:
The default availability:
The extra availability: