How to setups AME for Purchase Requisition?

Dear Experts,

I have some confusions regarding setups in AME for purchase requisition:

1) Through user management responsibility we have to assign roles for that user who will perform the setups for AME or for those users who will create the requisition and uses the AME work flow?

2) Through functional Admininstrator Responsibility while creating grants , we have to give grants for that user who will perform the setups for AME or for those users who will create the requisition and uses the AME work flow?

Thanks in Advance

Regards,

Jahanzeb