Backing up Your Pages
Occasionally you may find that you've made a change that needs to be reversed or, worse, that some of the content in the page you are editing gets erased or accidentally breaks. For pages that are heavy on content, technical aspects or just as a general practice, it's a good idea to make "back ups" of the code.
This is done by clicking on the HTML button 
in your toolbar, then carefully selecting all of the code or typing "CTRL" + "A" to select all of it. From here, you will want to copy and paste the code into a generic text editor, such as Notepad. Go ahead and save the text file with an easy-to-remember name.
Now that you have this code saved, you can feel free to make changes. As long as you have this back-up file, you can easily "revert" back to the original version of the page, by copying and pasting the code out of the text document and back into the HTML code view. This can also be helpful if you have a basic "template" layout set up for your pages and are hoping to preserve tables, layouts, etc - simply copy and paste the HTML code from one page to another.
Note - Remember, never paste HTML code directly into the main Page Content editing window!