This site is a central place to showcase the different building components that a content editor can use to build a site or page.
Download new Microsoft SharePoint 2016 tutorial here
In the right menu you can browse the differenet page layouts that can be used when creating a new page. Also you can see the page layouts available in a news site.
Under web parts you can see the different web parts available for adding to a page, each web part has a page showing it and explaing how to add/modify it.
CMS training sessions will be conducted soon by the Office of Communication on a periodic basis.