A full run-down of how to use textures in Cycles is a bit beyond the scope of this site. There are lots of good tutorials. BlenderGuru is a personal favorite.
In short, you'll create three texture nodes (I have no idea what the other three images on the right are for).
For one node, you'll load in the diffuse texture (top-left). That, you'll plug into the "color" slot of a diffuse shader.
For another node, you'll load in the normal map (middle-left). That, you'll plug into the "normal" slot for ALL the relevant shaders. For example, you'll probably mix together a diffuse shader with a few glossy shaders. You'll want to plug this into the "normal" slot for any of those shaders that are used on the head.
For a third node, you'll load in the spec map (bottom-left). That, you'll have to experiment with. To start with, plug it into the "color" slot of a glossy node.
Eventually, you'll want to mix your diffuse and glossy together. At that point, it may be helpful to ALSO plug the spec map into the "fac" slot of the mix shader that mixes the glossy and diffuse.
Now, this is the simplest possible setup, and it'll probably look terrible because it was designed for a different renderer. You'll want to insert some ramp nodes to control your B&W values. You may need to invert the color on some textures in order to get them to work right. Use RGB nodes to play with the colors until they look right. Look into how Blender uses Normal Maps. You sometimes have to do some strange things to get them to work right.
Lastly, if you want to use a PBR setup for your glossy (it's GORGEOUS), you'll want to look into how that's done in Blender (BlenderGuru has a recent tute on it). It's not terribly complicated, but it's also not terribly easy to figure out on your own.
Hope that helps!