Activate in the app (Earn More tab > More challenges).
- Choose and download/install a game from/through the ShopBack Play catalogue.
- Complete level 1.
It will ask for access to your usage data.
To remove ShopBack access to your usage data: Search for usage access or something similar in your device settings, scroll down to ShopBack and disable access.
I played Animals & Coins, level 1 took about 5 minutes? Maybe 10? I wasn't paying attention.