Forecasting requires a lot of repeating entries. Right now, this is handled in Helm using Frequency. Frequency equals the number of days that pass between each transaction in your rule.
Examples:
If you would like to setup a forecasting rule to create a transaction every month, Frequency = 30.
If you would like to create a transaction that occurs every two weeks, Frequency = 15.
If you don't want a forecasting rule to repeat (i.e. a single transaction on a single day), Frequency = 0.