The official documentation is at: http://docs.alfresco.com
Alfresco provides high-level customization and creation of applications through scripting and templating. Scripts and templates can be stored in the Alfresco repository, allowing easy creation and modification of Alfresco functionality.
With Alfresco scripts and templates, you can easily extend the functionality of the Alfresco web client or create complete new applications.
Template Guide - generate output, such as HTML and XML, from templates that can access Alfresco objects and queries. Templates can be used in dashboards and custom views within the Alfresco web client, as well as for generating new content.
Web Scripts - combine scripting and templating in a URL-based framework, which can run in portals, dashboards or other web containers; also can be used to provide custom data APIs.