Calculate 3D position from stereo Images

edit

I have intrinsic and estrinsic parametres of cameras and I have to rebuild the 3D from two images. I must work with OpenCv 2.4, C++

I'm not an expert of field, but reading on internet, I have understand that there are these steps:

A)Feature Detection from two images by SURF (example)

B)Rectification of two images and compute the disparity (depth map???)

C)Triangulation laser for recostrunction 3D

I would like to know these things:

1)Are the previous steps correct?

2)Are the camera parameters required for point C?

3)Can you help me with the implementation code of points B and C? I found some material, but I can not put it into practice