As an Approver (Budget Holders, Rubber Stampers or both), you have the ability to approve (as a Budget Holder) or stamp (as a Rubber Stamper) incoming requisitions if the total cost falls within a value bracket (purchase approval range) under which you have approval rights.
For instance, if you are responsible for moderating orders within the £500 – £1000 range, then all of the orders you are required to either approve or reject will have a total value within that range—the total value being the sum of all the items and the quantity of those items within a single requisition.
Depending on how your Direct-P2P Admin has configured your approval rights, you may only see orders from your section or department, and not your whole organisation.