A B-spline curve is more complex mathematically than a point curve. A B-spline curve's shape is determined by the number and location of its poles, which are represented as vertices of the curve's control polygon and its order.
The blue curve on the left is a point curve constructed at the end points of the black construction lines. The curve on the right is a B-spline, Through Point curve constructed at the endpoints of the black construction lines.
You can place a B-spline curve by entering data points or construct it by identifying a line string or shape.