How do I add npcs/humanoids locally?

So I’m going to attempt setting up a system for my game that loads all the npcs locally so it doesn’t cost server performance. How do I load the humanoid locally and keep the joints for the character?

I heard there’s a way to insert a model into workspace, and add all the parts a dummy has into the model and connect the joints together client sided, or server sided. How would I do this?

You can have the dummy in replicated first then weld it onto a hitbox the sever owns, so that the sever can like move it around and stuff then have the local script just render it.
I assume you know cloneing and all that jazz.