After downloading the Rig, first thing to make, be sure  blender has active self python script execution, this enables the operation of drivers and scripts contained in the character.

You can access this option through the "File" > "user preferences"  under the "File" tab 

for a quick reference you can see  the rig demo

https://youtu.be/JESe1PZeL-g

FK Spine 0:17
FK Arms 1:03
IK Arms  2:11
Fingers 3:35
IK Legs 4:32
FK Legs 6:38
Bend 5:36
Facial 7:39 (blend shapes)
Facial 10:47 (lattices)

Rig UI

The user interface is available selecting the rig of the model "ll_rig" in pose mode, and this has two main sections: "Body Rig" and "Facial Rig" 

Body Rig

By default the Body Rig is positioned with all zero values, FK chains for the arms and IK chains to the legs.

To enable IK chain arms just raise the value of  "FK-IK_arm" to 1 (one) in the sliders, this will make visible the IK chains for the arms.

Similarly, to enable the FK chain legs, carry the slider value "IK-FK_leg" to 1 (one), making FK chains visible.

The “Additional” button make visible an extra layer of controls capable of bend the mesh, this is especially useful for adding extra deformation to the model. 

Facial Rig

Under the label "FacialRig" are buttons that make visible the facial rig; these are divided into  Shape keys  and Lattices.

The shape key controls  are useful to create macro deformation, they  can generate gestures and expressions quickly, while the latices are more functional to polish expressions or breakdowns.

The Body Rig

Starting with the spine , the first bone in the hierarchy is "loc_rot_spine" that is located in the center of the model, and controls the rotation and column location. Selecting this bone, the  property "clamp"  appear, if the value is 0 (zero) all transformations are calculated relative to the "root" bone.

The following bones in the hierarchy order of descent are "CA_pansa" , "CA_pecho", "CA_cuello", "CA_cabeza" . the inheritance of rotation of these bones can be disabled with property "Rotation= 1" 

FK Arms

FK chains arms start from the shoulder and in order of descent are: CFK_hombro, CFK_brazo, CFK_ant_brazo  and CFK_mano; L and R respectively, rotation can not be isolated directly with a property and forearm rotation is limited to the axes "Y" and "Z" (normal). Stretching this chain occurs scaling the directly the controls,  the scale in the palm is regular.

The hand control for both the chain and the IK FK is an ovoid

IK  Arms

The IK  arms is controlled mainly from the bone "IK_mano" .L and .R, by default this control it is relative to the "root" bone, but this property can be changed by assigning a value1 (one) to property "Clamp" available when  the IK control is selected.

Stretching and contraction of the chain it is controlled by the  property "Stretch", available when selecting the bone "IK_mano" bringing the property value to 1 (one).

The second control of the chain is the bone, "polo_codo" .L and .R  this bone controls where the elbow will be pointing in your animation.

By default the poles are linked to  the control "IK_mano" but can be disassociated with his property "clamp".

Finally controls"CIK_hombro.L"and"CIK_hombro.R"control shoulder in the IK chain.

IK legs

The IK chain is controlled mainly by the bone "CA_pie" .L and R, transformation is relative to the "root" bone, but this property can be changed by assigning a value1 (one) "clamp"  property.

The  foot rotations occur  rotating the "CA_pie" control, however, the rotation with reverse pivot happens by scaling  the control in relation 1,5 : 90° (Scale to Rotation)

Stretching and contraction of the chain is controlled by the  property "Stretch" available when selecting the bone "CA_pie" bringing the property value to 1 (one).

By default the poles are linked to the "CA_pie" control, but can be disassociated with the property "clamp".

FK legs

The FK chains of the  leg,  starting from the thigh in order of descent are: "CFK_muslo", "CFK_canilla", "CFK_pie"  and "CFK_dedos"; L and R respectively, rotation can not be isolated directly with a property and rotation of "CFK_canilla" is restricted to the "Y" and "X"  axes (normal), stretching and contraction of this chain happens just Scaling the controls directly.

Hands and fingers

The master control for each finger are "menique", "anular", "medio", "indice" and "pulgar" .L and .R respectively, this control allows rotation of the first phalanx by simply rotating, and rotations of the following phalanges occur  scaling the control ( 0,5 : 90°), the rotation of the tip can be readjusted.

The opening of the palm is controlled by the bones "rot_menique" and "rot_indice".

The full palm can be closed bringing the value of the "Fist" to 1 (one) owned this property is available by selecting "IK_mano" or "CFK_mano".

Selecting the bone "root" you will be available the propeties "hair"  and "sub-surf", if the value is 1 this propieties make visible  the hair (particles) and subdivision surface in the viewport but that will not affect the visualization in the render, to prevent crashes do not use the both at the same times 

Some objects of this file cant be selected in the directly in the viewport, you can enable the selection via outliner.

And If you find some mistakes in this reference manual let me know  and I will fix

I hope you have many fun with this model!