SAP Purchase Requisition APP -- Enhancement Problem

Hi ,

Requirement is to add Field (Item Number )  in the Workflow Task  ,and (Purchase Group and Description ) in Item Details

i had activated the enhancements with Purchasing Group , but i am unable to get the field Fiori App.

and the Item Number is available in the Workflow task Structure(GBAPPS_PR_WORKFLOW_TASK), How to enable the fields  on Fiori UI.

Please find the attached Screen shots.

Kindly Guide me , Step by step details.

I had gone through so many links but unable to solve the issue

Regards,

Venubabu