An Idea's forecast amount values can be configured on the Idea Forecast section with a Forecast Type of Amount.

You can also import these values using the Import/Export module.

Once these values are entered, they appear on the Idea Benefit section as Forecast values. If Idea Forecast amount values are not specified, WiredUp will calculate these forecast bevalues based on the stage benefit percentages specified on the system. For more information, please see this article: Idea Forecast Values