This option is to make changes in the underlying screen. It allows to have two types of changes which are listed below:
Default Filter: It will let you display only allowed type of entries. You can tick the radio button next to the available options. It can be of one of the type i.e. All, Unread, Starred, Spam and Trash.
This option enables you to choose the number of forms that you want to list in single page.
Apply: Click on the blue button at the bottom left of the area in order to make your changes effective.