How can I make npc admin-only spawnable?

Hi

I am a total stranger and don’t know ANYthing to lua, so I wonder how I could prevent other users from spawning npcs, snpcs and such? I’ve been told I can create a .lua in autorun and put a list of npcs names, but I don’t know anything to lua, so yeah, if anyone could write the code and tell me where to put it, it would be really nice.