In this video, I go through the basics for backing up your System Center Configuration Manager (ConfigMgr) site and then step by step for the recovery.
For your backup, make sure you have the built-in task enabled or another backup strategy in place. Also, you will need to know the passwords for the accounts used in your site. In the console, you can go to Administration - Security - Accounts to see the list of accounts.
For the recovery process, you will start with the Splash.hta in the CD.Latest folder within your backup. Follow the wizard which is similar to the site installation process. When it is complete, you will need to re-enter the passwords for the accounts used in the site and run any other post recovery steps that apply to your environment.
Here are the links to the TechNet Documentation
ConfigMgr Current Branch: https://technet.microsoft.com/en-us/library/mt605292.aspx
ConfigMgr 2012 Versions: https://technet.microsoft.com/en-us/library/gg712697.aspx