BW refresh - Delete all source systems

Hi experts ,

We would like to refresh ou BW ( quality) from BW ( prod) using the SAP senario B2 .

I have to perform the foloowing activity in the SAP note , but i'm having doubt :

Delete ALL SAP source systems in the RSA1 source system tree of the target BW system. Caution: This step deletes all transfer rules and PSA tables of these source systems, and the data is lost. A message is generated stating that the source system cannot be accessed (since you deleted the host of the RFC connection). Choose "Ignore".

What means this step ? how to recover the copied source systems dépendant Objectq ( infpackages , transfert rules...)? how to execute correctly this activity ?

Many thanks for your help .