1. "Clone or download" project
2. open project
3. open main.unity in Assets/Scenes
4. play

• Click on empty field - create rectangle
• Click and drag rectangle - move rectangle
• Double click on rectangle - delete this rectangle
• Click on point of rectangle
  • First click - start creating realtionship beetwen rectangles
  • Second click (on point of another rectangle) - finish creating realtionship beetwen rectangles
• Double click on line between rectangles - delete this line

You can look at presentation of inital plan in InitialPlan.pptx