CiviCRM is an open source CRM built by a community of contributors and supporters, and coordinated by the Core Team. CiviCRM is web-based software used by a diverse range of organisations, particularly not-for-profit organizations (nonprofts and civic sector organizations). CiviCRM offers a complete feature set out of the box and can integrate with your website.
CiviMail installation consists of four parts: enabling the CiviMail component, setting up the SMTP configuration options, defining a cron job that will actually send the scheduled mailing, and choosing and setting up the return email channel.
Civicrm ERD link
CiviCRM documentation :
video tutorial CVcontribute:
Upgrading civiCRM from 2.1 to 2.2 documentation: