Some departments cannot use a revenue driver, as there are no patterns in the activity and revenue. E.g. Banquet or Conference department with activity not based on staying guests.
To do a manual forecast you have to calculate an expected revenue on the specific days you have activity and enter it in the Pickup column in the Live Forecast. E.g. if you have a conference on the 2nd of May and you expect them to generate 150, you enter 150 in the Pickup column on the 2nd of May.
You can export the Live Forecast to Excel or PDF for further reporting purposes.
Remember that the more accurate your forecasting is, the better you can optimize and plan your staffing, and see the outcome for your department at the end of the month.