The Side Panel offers a number of functions that are generally available in separate windows in most other word processors. The reason for doing this is to keep the amount of clutter on screen to a minimum and to make important functions readily available. You can drag the edge of the Side Panel with the mouse to resize it (although there is a minimum size), or, if you need extra screen space, you can switch it on and off with the F12 key.
The Side Panel has four tabs:
The "Files" Tab