This GitHub repository contains the source code that is used to build an Android app to control a FIRST Tech Challenge competition robot. To use this SDK, download/clone the entire project to your local computer.
If you are new to the FIRST Tech Challenge software and control system, you should visit the online wiki to learn how to install, configure, and use the software and control system:
https://github.com/ftctechnh/ftc_app/wiki
Note that the wiki is an "evergreen" document that is constantly being updated and edited. It contains the most current information about the FIRST Tech Challenge software and control system.