I am new to the field of Business Analytics. Can anyone distinguish between forecasting model, forecasting method and forecasting function? According to the book forecasting function is is an equation for calculating the forecasts over the forecast horizon. Then it provides the example for forecasting method as $$ F_t =b_0 + b_1 t$$ and model as $$Y_t = \beta_0 + \beta_1 t + \varepsilon_t$$
I can't understand any difference between these equations, because they all seem to be the equations with time as dependent variable and some constants. What is the difference in these equations that makes these three terms different?