This step-by-step guide will show you how to find your pre-built Outposts in Starfield.
Open your map and zoom out to see a full view of the map.
You will find two symbols hovering above some specific planet as shown in below image. These symbols serve as indicators that you have an outpost in this particular area.
Click on the planet displaying these symbols, select the planet, and go to that location. Upon your arrival, you can proceed to reach your Outpost.