Sourcing Workbench needs supplier approved - how do you do that?

PeopleSoft Purchasing Module version 41 and PeopleTools 8.59.

My place of work is looking into using PO Auto Sourcing. We are currently testing it in our non-production environment. We ran PO Auto Sourcing with Approved Requisitions and Staged Requisitions checked on the Objectives page. We left Pre-Approve Supplier checkbox unchecked under Purchase Order Options on the Options page.

One of the requisitions in the Sourcing Workbench has Stage Status Needs Approval. PeopleBooks says Needs Approval is set by the PO Calculations process once there are no errors and the purchase order is ready for building but still needs the supplier to be approved in the sourcing workbench pages.