Cannot change a TextButton's position?

I am making a GUI where you can select and delete stuff. For the deleting part, I want a shaking part. I have already done that. But I want it to like move the button's position, but it errors "Offset cannot be assigned to" whenever I put this in my script.

game:GetService('RunService').Heartbeat:Connect(function()
	if not deleting then --Activates if the user clicks the delete button, so it can stop rotating and repositioning.
		pcall(function()
			layout.Parent = script.Parent
		end)
		for i, v in pairs(items) do
			v.BackgroundColor3 = Color3.fromRGB(255, 255, 255)
			v.TextColor3 = Color3.fromRGB(27, 42, 53)
		end
		script:Clone().Parent = script.Parent
		script:Destroy()
	end
	
	if order == 'Asending' then
		position = position + .5
		for i, v in pairs(items) do
			v.Rotation = v.Rotation + 4
			v.Position.Y.Offset = v.Position.Y.Offset + position --This is the line that errors.
			print(v.Position.Y.Offset)
		end
		if items[1].Rotation == 20 then
			order = 'Desending'
		end
	elseif order == 'Desending' then
		for i, v in pairs(items) do
			v.Rotation = v.Rotation - 4
		end
		if items[1].Rotation == -20 then
			order = 'Asending'
		end
	end
end)

Remember, all of the variables are defined. "Items" is a table full of the buttons that the user can delete. Any idea?

Edit:

if order == "Asending" then
    position = position + .5
    for i, v in pairs(items) do
        v.Rotation = v.Rotation + 4
        local XOffSet = v.Position.X.Offset
        local YOffSet = v.Position.Y.Offset
        local X = v.Position.X
        local Y = v.Position.Y
        local FinalOffset = YOffSet + position
        v.Position = UDim2.new(X + 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X - 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X + 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X - 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X + 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X - 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X + 0.01, 0, Y, 0)
	wait()
	v.Position = UDim2.new(X - 0.01, 0, Y, 0)
	wait()
    end
end

Your script doesn't make much sense of what you want it to do. Fixed original script:

    if order == "Asending" then
        position = position + .5
        for i, v in pairs(items) do
            v.Rotation = v.Rotation + 4
            local XOffSet = v.Position.X.Offset
			local YOffSet = v.Position.Y.Offset
			local X = v.Position.X
			local Y = v.Position.Y
			local FinalOffset = YOffSet + position
			v.Position = UDim2.new(X, XOffSet, Y, FinalOffSet)
        end

However, using TweenGui, it will work better.

if order == "Asending" then
        position = position + .5
        for i, v in pairs(items) do
            v.Rotation = v.Rotation + 4
            local XOffSet = v.Position.X.Offset
			local YOffSet = v.Position.Y.Offset
			local X = v.Position.X
			local Y = v.Position.Y
			local FinalOffset = YOffSet + position
			v:TweenPosition(UDim2.new(X, XOffSet, Y, FinalOffSet), "Out", "Quad", 1)
        end

This will smoothly move the Gui.