Tello Flight Control is a free Android app developed by Blue Spectrum under the Utilities & Tools category. It is a demonstrator application for the Tello drone's "flight control SDK." The app allows you to connect your Tello drone to your Android device and control it using preset commands or by modifying the parameters of those commands.

To start, connect your drone to your device's WiFi and launch the Tello Flight Control app. The first command you need to send is "command" to place the drone in "command mode." After that, you can use the floating red "info" button to see a quick list of command types. The app provides you with a list of preset commands to choose from, and you can modify the parameters of those commands as well.

The app was tested on Samsung S6 (Android 7), Samsung S3 (Android 4.4), and Samsung Note Pro 12.2 tablet (Android 5). However, keep in mind that when entering commands, you will need to wait for the previous command to finish before entering a new one. The Tello drone does not indicate whether it's busy or finished, so you'll have to visually identify when a command has completed. Overall, Tello Flight Control is a useful app for controlling your Tello drone with ease.