In order to activate Fair Choice in your Android app, you need to create either a subscription or an in-app purchase and link it's ID to the corresponding Asset in the consent settings page.
This creation can be managed on the Google Play console for both subscriptions and managed products. To create a subscription, you can refer to Google's documentation for subscription creation. To create an in-app purchase, you can refer to Google's documentation for managed product creation.
When you have successfully created your in-app purchase, you can copy & paste the ID of your newly created in-app purchase on the consent settings page.
The ID can be found in the following location in the administration interface:
Managed product Id