When you are setting up your mobile app unmoderated project, make sure to select "Smartphone" as the device you'd like testers to take the study on. Select the operating device you would like your study to be completed with.
Select your Audience; Total number of participants, Demographic, Employment. Screener questions and other testing requirements if necessary.
Continue through the process of setting up your study. Once you've landed on the "Create Questions" step, you are going to input the URL to the App Store or the Play Store.
For example:
This is the App Store URL for the Disney App: https://apps.apple.com/us/app/disney/id1446075923
This is the Play Store URL for the Disney App: https://play.google.com/store/apps/details?id=com.disney.disneyplus&hl=en_US
Next you can add your task instructions!