Need help with blender and rigging custom model to TF2 Spy

I’m trying to rig Ghirahim’s model from Skyward Sword to the Spy’s skeleton for use as a custom model on my tf2 server, however I have no idea where to start. I have a decompiled blender-ready, spy model and the ghirahim model from skyward sword on hand, and then the blender version off steam.

Could someone give me a tutorial on how to do this?
I’ve downloaded the Ghirahim model from here
And the Blender TF2 Models from here

Anything would be appreciated.