If a form has already been set, you will see the title of the form displayed.
To change the form, click on [Selected initial form]. If you do not want to set a default form, click on the [X] button.
After you click on the selected default form, a list of possible forms to set up will open.
Choose the desired form and confirm your choice by clicking the
[select] 
button.
If a default form has not yet been set, click on [Select form] to also see the list of available forms. You select the desired form in the same way.