To perform a forecast using NumXL, select the cell of the model's table (i.e. AirLine).
Click on the "Forecast" icon in the toolbar.
The forecast wizard will pop up. Select the realized observations (i.e. tail points of your sample data), and the forecast horizon in units of steps.
In the illustration above, the last 23 observations in a sample data was chosen, then the forecast horizon was set to 30 steps (or units).
Plot the forecast and its' confidence intervals.