Did you create a new path such as: /newpage/index.html ?
As for html knowledge... the most recent builds contain a wysiwyg editor in the manage html section.
No, didn't create a new path. The 404 message shows RequestURI=/new_page.html.
This alpha must not include the WYSIWYG editor. I see no reference to it.
you need to specify the url as
if you don't want the "nukes" extension, you have to edit the local.properties file in "build" to modify the context root entry to just be "/"