If you open Atlas Arcade and no games populate, it's possible that you've already played all the games on offer at that moment on your device before (you may have them downloaded at the time or have had them downloaded in the past). In this case, you can check back later to see if there is something new.
If this is not the case (i.e. if you have never had any games downloaded on your device), please reach out to Atlas support (not the support button in the Arcade).
Arcade Availability Disclaimer
ATLAS:EARTH Arcade access is determined by the country where you originally downloaded the app. If you downloaded ATLAS:EARTH in the United States and later travel or move to another country (e.g., Mexico or Canada), the Arcade feature may not be available in your new location. At this time, we are unable to change or update your country of origin within the app. We appreciate your understanding and are actively exploring solutions for future updates.