The Content tab of the Articles main tab contains opened article - one content tab for each opened article.
Every content tab is split in the following panes:
•Article tree and attributes pane (on the left side)
•Article source pane (in the middle)
•Article WYSIWYG / Web pane (on the right side)
All panes are collapsible and resizeable.
Use the Table of Contents to find information. See also Using table of contents in help.