To get started, make sure you meet the dependencies and install everything. While things are compiling, it might be a good idea to familarize yourself with the literature, starting with a shameless plug for my papers:
Hellman, O., Steneteg, P., Abrikosov, I. A., & Simak, S. I. (2013). Temperature dependent effective potential method for accurate free energy calculations of solids. Physical Review B, 87(10), 104111.
This provides background, but does not accurately reflect all the capabilities of this software package.
This software package consist of several programs, meant to be chained together into workflows, depending on property you are interested in. Before trying anything too complicated, make sure you start with the tutorial, everything named minimal example. The descriptions of each program serves as both reference and theoretical background. For things to make sense, read them in this order: