Groundwork is the base for your horse in which you work together whereby communication, increase mutual respect and trust, prepare the "young" horse for further training. It is also a nice change in riding and lunging.
To start with groundwork, you need a few tools; this depends on performing groundwork.
According to the Natural Horsemanship methods, you use a rope halter, lead rope, and a carrot stick with string.
According to the principles of Classical and Academic Art of Riding, or Straightness, you use a cavesson, a short or shortened lunge line (minimum 6 meters), and a stick (whip).