How can an approver see the files that were uploaded as part of an order?

If an approver needs to also review the files that were uploaded with an order you'll need to make changes to the approver's site group. The permissions "Can Approve Same Location" and "Can Approve Same Site" should both be set to Allowed. When this is done any user in the approvers site group will then be able to see the files uploaded with an order and can review them for approval.