Garen or Malphite. Depending on what type of champion you prefer (fighter or tank), but these two are super easy to learn in toplane, and they are the best to learn the basics of wave control, rotations, clearing the wave, etc. Garen has good sustain, good wave clear, easy to learn how to farm with, easy to chase down, and is kind of tanky and is a champion that is very forgiving if you make mistakes. Start with Garen if you are new, you won’t be dissapòinted.