Like when you have a bunch of parts in a model, the model doesn't have a position property, so you can't change it that way. I've seen it done in games. How would you do this?
local Model = game.Workspace.ModelName Model:MoveTo(Vector3.new(300, 5, 840)
This is based on the PrimaryPart of the model. If you to move the model such that a certain part of the model will be at the given position, set Model.PrimaryPart to that part of the model.