Undefined reference for a specific library: FastNoiseSIMD

I'm new to C++ and I'm trying to include a header file from this library, http://ift.tt/2cWMaO1

When I write this line, FastNoiseSIMD* myNoise = FastNoiseSIMD::NewFastNoiseSIMD(); I get the error: main.cpp:36: undefined reference to FastNoiseSIMD::NewFastNoiseSIMD(int)

Here is how I'm including the header:

#include "FastNoiseSIMD/FastNoiseSIMD/FastNoiseSIMD.h"

As you can see, the files are in folders that are located in the working directory of my program. I'm working on Linux using c++11 and g++. I don't see any library files that I need to link so I'm stuck here.

Any help is greatly appreciated. Thank you.