Once you added items or services into your shopping cart and updated the requisition details (ship to, accounting, notes, etc) and just before you are ready to submit, choose next.

On this screen you can first of all validate the approval process that was generated by oracle.  By clicking on the chain of command the system will display a new screen showing the default approvals

Once you returned to the previous screen choose Manage Approvals.

On this screen you can choose to insert an approver by searching in the Approver field using the last name of the Herc employee you want to add.

You now can choose the position in the chain for the new approver. When done choose submit. You can repeat the process as many times as you want in order to get other additional approvers into the approval chain. When done you can submit your order and the approvers (default and extra) will be asked to approve in the order you placed them.