with this code
wait(60) -- Wait 1 minute
local enemy = game.ServerStorage["Drooling Zombie"]
local spawn = game.Workspace.Spawn
while true do
local c = enemy:Clone() -- Clone the enemy model.
c.Parent = game.Workspace -- Parent it to the Workspace.
c:MoveTo(spawn.Position) -- Move the enemy to the center of Spawn's position.
end

2 comments
Im sorry, but what do you want to mean?
dont do while true do when making parts add a wait() like while wait(1) do end or while true do wait(1) end