As with many models done in box modeling, let's start with a cube. The model is symmetrical so let's make use of it. Add a loop running vertically at the middle and delete the vertices on the left, leaving you with only half of the cube. Now add a mirror modifier.
Now add a loop running horizontally and fashion out the torso.
Forming the torso
Add a vertical loop on the torso so that we will have more geometry to work on.
Adding more geometry
Extrude the head and the legs. Add loops around the head and the bottom of the legs and extrude out the head and feet.
Extrude head and legs
The model at another view
Now add a loop around the torso and extrude out the arms. This is all for blocking