Get a Planetary Chart for Alien Structures from a Cartographer
Use the chart on a planet in the system
Look for a Monolith marker
Travel to the Monolith
Interact with the Monolith
Answer its riddle correctly
Offer the requested race-specific relic if needed
Ask the Monolith to locate a portal
If it does not reveal one, use another chart or find another Monolith
Repeat on different planets until a Portal is marked
Use an Exocraft with an upgraded scanner to search for alien structures faster
Use the Signal Booster only if you already know the portal coordinates from another source
Check space station mission boards or community tips for portal-rich planets
Activate the Portal by charging its glyphs after you find it