Creating Expression Types 
In the Object Manager panel, under the Detail section, choose the Assigned Objects tab.
In the Assigned Objects tab page that appears, choose Expression Type from the Type field and choose Create Object.
In the Object Creation dialog box that appears, enter the following data:
Name
Short Text
Text
Choose Create & Navigate To Object.
The newly created expression type appears in the Object Manager panel.
Note
If you choose Create the newly created expression type appears under the Assigned Objects tab page.
In the General subsection, enter the following data:
Class
Enter the name of the class that implements the interface.
Interface
Enter the name of the interface which contains the specific attributes for the expression type.
Query Class
Enter the query class. Query class provides an interface that searches for objects and returns details of the object which satisfies the selection criteria.
UI Class
The UI class provides a corresponding expression type object needed to create the expression type.
Data Exchange Class
Enter relevant details in Transport Objects section.
Save the expression type.