13.3.1.2 Source Process Tab
Use the Source process tab to specify an Allocation rule's data source. For an Allocation of the Constant type, you simply specify an amount. For any other type of rule, you must specify a source table and column and, optionally, a set of constraints. Alternatively, you may specify an Expression to specify a more complex Source than a simple source table and column.
For Pane: Choose a source table and then choose a column from that table or choose an Expression rule.