How to add ragdoll on a model that has no "root handle" prefab together??

I have downloaded a zombie character model from unity’s asset store, which is free.

Now i trying to make a ragdoll for it, but when i try to locate the root for it, it doesn’t comes together with the zombie character pack that i downloaded.

So i wan to ask is there anyway i can add ragdoll on it without the “root handle”???

Please, try searching next time.