To get information on how your Apple TV app is performing in terms of installations, sessions and retention we recommend you check out the App Analytics page of iTunes Connect.
Therefore login to your iTunes Connect Account here: https://itunesconnect.apple.com/login
After login click on the 'App Analytics' button (https://analytics.itunes.apple.com/) and select your Apple TV app.
You will then see analytics data like:
Impressions
Product Page Views
App Installations
Sessions
Retention
In the 'Sources' Tab you can see the breakdown of that numbers by source type. So for example you can see how many people installed your app via 'App Store Browse', 'App Store Search', 'App Referrer' etc.