Saving your page frequently will make sure you never loose any important work.
Save using the Save button
You can save your work by pressing the Save button in the lower left side of an editing window
Save using the shortcut keys
You can save using the standard shortcut keys on your computer.
On a Windows machine the shortcut is CTRL+S
On a Mac the shortcut is CMD+S
When you save a page, those changes will be live on the web.