It's good practice to backup your site regularly and before making major changes. There are two extensions we like for backing things up: 
  • Akeeba Backup
  • Easy Joomla Backup 
Here's how to backup your Joomla site using AkeebaBackup

  1. Log into your administrator panel
  2. From the Component menu select, AkeebaBackup  Components > Akeeba Backup

  3. Click the Backup Now button
  4. You can add a comment to the backup such as: "before adding January events" 
  5. Click the Backup Now! button under the comment box
  6. You can watch the progress, do not navigate away from the screen until complete
  7. Upon completion you will see a Backup Completed message
All Done!