Exponent apps have URLs, so if you have the URL for an Exponent app, you can just download the Exponent developer app from the iOS App Store / Play Store and then open the URL.
If you have the source code for the app, just open the project directory in XDE (our desktop software) and it will give you a development URL that you can open in the Simulator or on your phone.
In general, testing Exponent apps is way easier than testing apps other ways. We put a lot of time into making it simple.
Ex. Try opening https://getexponent.com/@exponent/floatyplane from your phone.
If you have the source code for the app, just open the project directory in XDE (our desktop software) and it will give you a development URL that you can open in the Simulator or on your phone.
In general, testing Exponent apps is way easier than testing apps other ways. We put a lot of time into making it simple.