Making Ragdolls for Garry's Mod using 3DS Max

So, after looking at several tutorials, I finally got to here with a model… (Regal Bryant from ToS)
It’s imported as a SMD file.
As you can see, it has bones and it should be rigged, but how to I make it/export it into a ragdoll for gmod?
Any tutorials or advice would be greatly appreciated.