Box2D integration


Is there something in particular that I need to do in order to use Box2d? When I try to define a b2Vec2 the compiler complains that b2Vec2 was not declared in this scope. Is there a header file I need or do I need to download box2d or something? I was under the impression that it was included.

EDIT: I am using 2.2


#include “Box2D/Box2D.h”