1 To plot a point on the graph, move the mouse pointer over the grid area. The point is displayed at the location of the mouse pointer. The value for the point is displayed on the vertical axis. The time period for the point is displayed on the horizontal axis.

2 Move the mouse to the required value and time period coordinates, and then click to enter the data point. This new data point is the likely, or nominal estimate for the required value.

3 To enter a second data point, move the mouse pointer to another time period on the grid. As you move the mouse pointer within the grid area, the value and time axes are updated to indicate the data point. Click to enter the data point.

4 A new likely estimate is automatically entered and a line is drawn between the first and second estimates. Any data between the two estimates is added based on the trajectory of the connecting line.

5 Enter new data points by moving the mouse pointer, and then clicking to capture the data points. A smooth curve is drawn from the data points and data is added from your input.