The WBS Picker field in a business process form has an additional toolbar option (Source) that shows the source value as either P6, Primavera Cloud, or Custom. The Source field drop-down will display "Custom" by default and all of the WBS Codes from the Project WBS Sheet will be shown.
You can switch between different sources (P6 or Primavera Cloud and Custom) if your project has both Project WBS Sheet and System WBS Sheet. The WBS Codes created from the selected source will be shown in the Picker window.
To select the code, the WBS Code shows the entire path.
You can select a unique WBS Code to add a cost transaction.