Entering and Exiting Edit Mode
To start making changes to your page, click the Edit Page button.
The page will reload with all editable areas highlighted by dotted red borders.
This is where you can insert and edit content blocks. Just click on any block and select Edit from the pop-up menu.
You'll also notice that new buttons have become available on the toolbar: Properties, Design, Permissions, Versions and Move / Delete.
Once you have the page looking the way you like, click Exit Edit Mode to save your changes. You will get the option to either Preview your changes (for just you and other Admins) or Publish them live for the whole world to see.