This is the error I get:
ServerScriptService.ServerPlacement:2: attempt to index nil with 'Clone'
And this is my script
local function Place(data, location, pos)
local model = game.ReplicatedStorage.Models:FindFirstChild(data.Name):Clone()
model.PrimaryPart.Transparency = 1
model.PrimaryPart.CanCollide = false
model:SetPrimaryPartCFrame(CFrame.New(pos.X, pos.Y, pos.Z) * CFrame.Angles(0, math.rad(data.CFrame.Rotation), 0))
model.Part = location
end
game.ReplicatedStorage.Events.PlaceObj.OnServerEvent:Connect(Place)

3 comments
Instances in ReplicatedStorage may not have loaded yet, try using WaitForChild()
That brought this error: Infinite yield possible on 'ReplicatedStorage.Models:WaitForChild("DemonMildzz")'
Silents his post makes no sense, if this is called by an OnServerEvent it means it could never possibly be running at game start. So a few seconds after you have joined. Everything is already loaded in ReplicatedStorage.