Name, Description
  Enter the Element Type's name and a brief description.
Page
  Checking this checkbox makes the Element Type a page. This means that if a Story has more than one Page element, a separate (HTML) file will be created for each page.
Fixed
  This determines whether the Element Type fill have a fixed URL. This is generally used in "Cover Pages", which link to several other pages and whose URIs shouldn't depend (for example) on the date that the Cover was created.
Related Story, Media
  All Elements can have one story and/or one media object associated with them. Checking these boxes allows users to do this.
Type
  The type can be either Story, Media, or Element. An element with a type of Story or Media is a top-level element. All other elements are of type Element, which can be added to other elements as subelements. When creating a new Element Type, you have to select the Type on the first page, as other options depend on this property.

If you want to delete the the Element Type, check the 'Delete this Profile' checkbox. When finished, click Save.