If you’ve navigated away from where you ended the previous step, enter Approval Processes in the Quick Find box, then click Discount Approval Process from the Inactive Approval Processes section.
From the Add New picklist in the Initial Submission Actions section, select Field Update and complete the field update details with these values:
FieldValueNameApproval Status Pending
Unique Name[this field auto-populates]
Field to UpdateApproval Status
Picklist Options: A specific valuePending
Click Save.
Next, create approval steps.
Click New Approval Step and complete the details of the first approval step:
FieldValueNameManager Approval
Unique Name[this field auto-populates]
DescriptionDiscount approver must approve discounts over 15%
Step Number1
Click Next.
Select the Enter this step if the following radio button, and choose criteria are met, else approve record then fill in these details:
FieldOperatorValueOpportunity: Discount Percentagegreater than15
Click Next, then complete the assigned approver information:
Select the Automatically assign using the user field selected earlier (Manager) radio button.
Deselect The approver’s delegate may also approve this request checkbox.
Click Save.
On the What Would You Like To Do Now? page, select No, I'll do this later, take me to the approval process detail page to review what I've just created.
Click Go!
In the Approval Steps section, click New Approval Step and complete the details of the second approval step:
FieldValueNameVP Approval
Unique Name[this field auto-populates]
DescriptionVP North American Sales must approve discounts over 40%
Step Number2
Click Next.
Select the Enter this step if the following radio button, and choose criteria are met, then fill in these details:
FieldOperatorValueOpportunity: Discount Percentagegreater than40
Click Next, then complete the assigned approver information:
FieldValueSelect ApproverAutomatically assign to approver(s)
UserAllison Wheeler
Approve or reject based on the FIRST responseselect
Approver’s delegate may also approve this requestdeselect
Reject BehaviorPerform all rejection actions for this step AND all final rejection actions (Final Rejection)
Click Save.
On the What Would You Like To Do Now? page, select No, I'll do this later, take me to the approval process detail page to review what I've just created.
Click Go!

So I followed those instructions and created this:

There's too many screenshots to attach, so let me break it down:
1: Approval Status ending - specific value = Pending
2: Manager Approval:

- Set to "Criteria are met, else approve if Discount Percentage greater than 15
- Automatically assign to Manager

3: VP Approval:

- Set to "Enter this step if the following criteria are met": Discount Percentage greater than 40
- Automatically assign you Allison Wheeler
- Perform all rejection actions

So, please help me identify why it's not working, despite me following the instructions to the letter.  I'm baffled.

Cheers, Nat