AME for AP Invoice Approval

PHello

This is on r12.1.3

I am new to AME and I am not sure how to set up following.  Below is the detail requirement. We need to set up AME flow for AP Invoice approval. Can any one guide me through the process?

Payable Invoices that have a Purchase Order.

-All invoices needs to be approved / confirmation of services
-First the PO requester need to approve.
-Above 100K Cost Center owner approval
-Multiple cost centers – maximum $ amount

Payable Invoice without a Purchase Order

-Based on the delegation of Authority Matrix
-Approver.
-Manually select  the approver (Requester)
-Move it up based on delegation (job Level)