Uncomment the Template.cpp or CameraTemplate.cpp file and compile with the following command:

g++ -o Template *.cpp -lSDL2 -lSDL2_image -lBox2D -lao -lsndfile

Note: I have add a very small example contains Main.h Main.cpp SteelChain.cpp SteelChain.h a.wav b.wav make.sh and the binary file SmallProject. If you wanna compile one of the Template.cpp or CameraTemplate.cpp file, comment the Main.cpp