Hello,
A lot of the documentation is built right into the demo sites themselves. Be sure to check the drop down menus for things like Extensions, Site Specific Tutorials etc.
http://shape5.com/demo/wp/vertex/Following that we have Wordpress Specific Tutorials here:http://www.shape5.com/wordpress/tutorials/tutorials.htmlAnd the Vertex Guide here:This one is specific to Joomla but a lot of the content translates the same to Wordpress.
http://www.shape5.com/tutorials/joomla/s5_vertex_guide.pdfIf you have any specific questions not covered in those areas please let us know in the forums and we can assist you from there.
Regards,