Sometimes forward kinematics is useful for articulate posing, but more often inverse kinematics is what delivers the most natural movement. With this model, you can toggle between these two states by using its special context menu as highlighted in the picture below:
You can turn parts of the rig on and off through the Rig Layers dropdown. This can visually simplify your work.
...and the Rest is Basic Blender 3d
Rigify is the only advanced aspect of this model. The model is rigged properly with the existing Rigify rig, so everything else is basic Blender 3d work.
Please note on the product page that this particular model does require a working Blender 3d knowledge, and the model should not be purchased without having a suitable designer available.