The "Position" window shows the parametric curve (x(t),y(t)).  It also shows a green vector that is the velocity vector at the point (x(t0),y(t0), and a red acceleration vector at (x(t0),y(t0)).  Modify t0 in the control window.

The "Velocity" window shows the velocity vector in green based at the origin, and the accleration vector in red based at the end of the velocity vector.  Changing t0 will trace out a curve of x'(t) versus y'(t).

The "Acceleration" window shows the acceleration vector in red based at the origin.  Changing to will trace out the curve of x''(t) versus y''(t).