Access content area for editing

You must have your page checked out to edit your content.

Click on the "Edit" button at the top of your page if it is not highlighteld ("Preview" is highlighted in the image below). 

edit tab

Once the edit button is the active (highlighted) button, you will see the green "Main Content" button.

Click on the green 'Main Content' button. If you do not see this button then you are not in "Edit" mode.
main content

You will then be in a WYSIWYG (what you see is what you get) window and can now edit your page. The tool bar at the top is fairly similar to an MS Word toolbar.

what you see is what you get toolbar