When a participant opens the app for your event, they first see the splashscreen, then the cover (s) (if they were created), and then he/she is redirected to the default service of your app.
This default service, which is the first feature on which your participant will be redirected, can be modified.
Go on "APP", "Manage App" and then click on "Web".
From the "Default service" dropdown list select, choose the feature that you want set as the first feature to be seen.
Click on the "Validate" button to the bottom right corner.