The Mission Map is visible when you Zoom the 
Mission View.  It displays the current Mission in tree form, making it easier to construct and navigate  multi-step Missions.  Mission Steps are displayed in order, with optional sub-steps shown indented.  Clicking on a Step displays the settings for that step.  Clicking on + or - shows or hides the sub-steps.  Steps are added or deleted using the First, Then, and Delete buttons in Mission View.