Class Diagram, modelling aggregation

I am adding a class diagram to the logical modelling section of a Capella session.
I want to model a class having a collection of other classes in the same diagram.

For example I have a class called Organisation and I have a class called Employee and I want to have a property on the Organisation class called employees that is a collection of Employee classes.

I have tried adding a Property to the Organisation class but to be able to specify the Employee class as the type I first have to check its “is primitive” checkbox which then makes it not possible to show the aggregation relationship. Also there seems to be no array primitive.

Can anyone explain the correct way to model this basic relationship with Capella?