Run the tween on a GUI and not a part?
You can’t animate parts using TweenService only, you’ll have to connect that with the CFrame position values through the script.
For the GUI, change the part to an interface object, such as a Frame, TextLabel, or a ImageLabel.
Vector3 is not a property of gui’s. Vector3 is used for 3D space in Roblox, typically for positioning, rotating, and sizing 3D objects in the game world.
For GUI elements, Roblox uses a different data type called UDim2. UDim2 is used to position and size GUI elements relative to their parent container. It uses a combination of scale and offset to determine the final position or size. Scale is a value between 0 and 1 that represents a fraction of the parent container’s size, and offset is a value in pixels.
-- Set the size of the GUI object
guiObject.Size = UDim2.new(0.5, 0, 0.5, 0) --set these to your preferred sizes