There are tutorials on templates in the SDK documentation section http://ez.no/sdk Check http://ez.no/developer/ez_publish_3/documentation for more support
I customised demo first to get the hang of it.
In demo/override/templates I customised them first.
i.e. for the news page I customised pagelayout_section_3.tpl and to customise the classes I did it in demo too.
You will also need to customise in demo/override/templates/nodes/view for the news it is the # 2.tpl (full and line)
