How to use Tensor Method with own data

Hello and sorry to bother you:
  I'm very interested  in Tensor Method for Latent Variable Model or Gaussian Mixture Model and I'm puzzled that How could I use it with my own data.
  Specially,  how could I obtain A before I import data, A is the means of the Gaussian mixture components. I have seen it in your code https://github.com/steverab/tensor-gmm/blob/master/matlab/tensor_gmm.m