OOONA is a cloud-based platform.
To set time interval for the automatic backup, go to Settings->User Configuration->General Tab.
Manual Save
You can click on click on Project->Save in the menu or the Save button on the toolbar.
You can also use the save hotkey. The default value is "Ctrl+S". You can check what hotkey is associated with the "Save current project" action in the hotkeys dialog. If you have a poor internet connection, make sure to backup your project locally. To download a project to your computer, click Project->Download project.