how to make an event if it does not find a first child?

local remoteevent = game.ReplicatedStorage.ResetServer

local function ResetServer()
	game.Lighting:ClearAllChildren()
	game.StarterPack:ClearAllChildren()
	game.ServerStorage.Baseplate:Clone().Parent = workspace
	game.Lighting.FogEnd = 100000000
	game.Lighting.Ambient = Color3.fromRGB(0,0,0)
	game.Lighting.OutdoorAmbient = Color3.fromRGB(128, 128, 128)
	for i,v in pairs(workspace:GetChildren()) do
    if v.Name ~= "Terrain" and v:FindFirstChild("Humanoid") then -- here should be does not find first child
        v:Destroy()
wait(1)
game.ServerStorage.Baseplate:Clone().Parent = workspace
    end
end
end

remoteevent.OnServerEvent:Connect(ResetServer)

Hello, here is how:

local remoteevent = game.ReplicatedStorage.ResetServer

local function ResetServer()
    game.Lighting:ClearAllChildren()
    game.StarterPack:ClearAllChildren()
    game.ServerStorage.Baseplate:Clone().Parent = workspace
    game.Lighting.FogEnd = 100000000
    game.Lighting.Ambient = Color3.fromRGB(0,0,0)
    game.Lighting.OutdoorAmbient = Color3.fromRGB(128, 128, 128)
    for i,v in pairs(workspace:GetChildren()) do
	local find = v:FindFirstChild("Humanoid")
    if v.Name ~= "Terrain" and not find then -- if not that object, than destroy.
        v:Destroy()
wait(1)
game.ServerStorage.Baseplate:Clone().Parent = workspace
    end
end
end

remoteevent.OnServerEvent:Connect(ResetServer)

Hope it helps!