The library is for Teensy microcontroller (client) that communicates with ROS-running computer (server) via rosserial node.
It is designed to work with Blue Robotics T100 thruster, for surface vehicle with "+" configuration. For detailed descrpition and pictures see thrust_allocation.pdf (here) inside docs folder.
The .cpp .h files should go to ~/Arduino/libraries folder and thrust_allocation_example.ino should be in sketches folder.