[SOLVED]Import Box2dTestbed from samples to project?

In this directory …\cocos2d-x_3-9\tests\cpp-tests\Classes\Box2DTestBed, there is files for the testbed working in cocos2d-x.
But the problem is that I have no idea about how I should use them in my project or just in a place where I can take the files in use. Any idea?

Thanks!