We work great across platforms and this is the ideal setup as we can provide a lot more functionality for Android child devices.
To start, download Boomerang on your iPhone, select "I'M NEW" and "MANAGE FAMILY DEVICES" and then create your account using your email and a password.
Then, download Boomerang on the child devices and select "LOGIN" and "CONTROL THIS DEVICE", agree to the permissions, complete the onboarding wizard and enroll using your email and password - the devices will then pair and you will see them in your iPhone.
Watch this video to see all the functions that you can do from your phone: https://youtu.be/t9Lg5ToRWTw but not all management and configuration options are currently in the iOS parent mode so do login and use the web management dashboard.
To configure the Android child device completely, use the Web Management Dashboard. Watch this video: https://youtu.be/6shLpbyNyXI.