Workflow escalation to next level in hierarchy

I am in the process of configuration the purchase requisition workflow.

My "approval" step is using the organizational hierarchy and approval limits assigned to each person in the hierarchy - this is all working well.

I am now trying to set up an escalation which I thought would be quite simple: If an approver did not approve within 2 days (for example) - I want the workflow to escalate the next level above them in the hierarchy.

so on the approval step, I turn on the "Use Escalation Path", and I assume the "Assignment Type" should be "Hierarchy"?

On the "hierarchy selection" what should I select?

Or is it done completely differently?

I assume the "