If you select the Layouts tab at the top of the Radiant administration interface you’ll be presented with a list of layouts or an empty list if you’ve never created any before and chose the “Empty” database template. The New Layout button at the bottom of the list leads to a form consisting of name and body text fields. Below the name field is a small More link, which if selected will add a content type field to the form.
Layout names cannot contain spaces or tabs. Sticking to lower case letters with hyphens or underscores separating the words is a reasonable rule. File extensions are not necessary. There is an internal 100 character limit on name lengths and layout names must be unique.
As well as including page content and Snippets, one layout can include another layout, which is where the content type field comes in – layouts default to HTML, but you could, for example, create a layout for containing your Atom feed by setting the content type
Last edited by johnmuhl,