How to make my part Placement system make parts move in a grid accordingly of where it is on a part?

I'm trying to make a build system in my game and when you move your mouse it fires a function which is supposed to make the part move by 2 studs but when you move your mouse it moves 2 studs but it isn't in grid or orientation accordingly to where the grid texture is on the baseplate. Here's my script (portion of it)

local function SnapToGrid()
	PosX, PosY, PosZ = math.floor(Mouse.Hit.X / Grid + 0.5) * Grid, math.floor(Mouse.Hit.Y / Grid + 1) * Grid, math.floor(Mouse.Hit.Z / Grid + 0.5) * Grid
end

local function MouseMoved()
	Object.PrimaryPart.Position = Vector3.new(PosX, PosY, PosZ)
	SnapToGrid()
end

local function CloneService(Obj)
	Object = game.ReplicatedStorage.BuildObjects:FindFirstChild(Obj):Clone()
	Object.Parent = Plot
	
	Object.PrimaryPart.Orientation = Vector3.new(0, PlotY, 0)
	Mouse.Move:Connect(MouseMoved)
end

Soil.MouseButton1Click:Connect(function()
	CloneService("Soil")
end)

Can someone tell me how to make the moveable part align up with the baseplate and move by two studs. When it does move the part it goes somewhat diagonal. please HELP!