From the watch face, swipe up or long press the lower button to get access to all of the watch settings via the Control panel.
The settings menu can be accessed directly if you long press the middle button while you are in the watch face view.
If you want quick access to a certain setting or feature, you can customize the top button logic (from watch face view) and create a shortcut to your most useful setting or feature.
To define a shortcut for the upper button, open the Control panel and select Customize followed by Top shortcut and select what setting or feature the top button will have when long pressed.