1. Click the View tab on the PowerPoint top menu
2. Double-click the Normal option on the far left side of the menu. Even if you are already in Normal view, this will reopen the navigation panel on the left side of your PowerPoint slides
3. Click the Outline tab from the navigation panel to view and edit your slide show’s outline

Note: If you still don't see the Outline tab, hover your mouse over the vertical line on the left side of your screen, click the left mouse button and drag the line to the right until you see the Outline tab appear in the left pane.