Here is a step by step guide to creating simple Update plugin in CRM 2013 on the account entity. The plugin is created using the CRM 2013 Developer Toolkit
The video also explains some of the options in plugins
Here is a link to the step by step blog post
http://crmbusiness.wordpress.com/2014...
The follow on video is here
• CRM 2013 - Simple Plugin - Redeployin...