Particle generator with Rajawali

I started doing the tutorial for: http://ift.tt/1fBsNGB I need to make a particle generator, in my app, and while looking through the list of tutorials I went over this: http://ift.tt/1LvWZl2 But this page just shows me some code, and a link to another github page. Looked over the code, but I don't understand where I should set it. I don't even have a ParticleSystem class in my app. I Went on the link with the github page, and I found this here: http://ift.tt/1fBsM5H Tried to create this class as my particle System, BUT my project doesn't see the ParticleMaterial Class. It is not part of my code. Have anybody else tried to make a particle generator with this library, if so, what could I be doing wrong?