If you press 'start' on a stop, Circuit will send your stop to Google Maps and navigate you to that stop. It's possible to change the default navigation app to any navigation app of your preference: Waze, Google Maps, Apple Maps or any other navigation app of your preference.
To change your navigation app:
open ☰ Menu;
Choose 'Settings' ⚙️;
Click 'Navigation app' ;
Choose 'Google Maps', 'Waze' or 'Other';
'Other' will allow you to use any navigation app you've installed on your phone. Next time you press the 'start' button on a stop, you'll be asked to choose the navigation app of your preference.