Serial Mode approval Rules

Summary: Need to define the approval rules in 'Serial' Mode

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Hi Team,

My current expense report approval rules are working fine in 'Parallel' mode, have configured like below. But I noticed, it is getting assigned in 'serial' manner like it will go to another approver once it is approved by the previous one, which is fine with me, till the time approvers receives the approval notifications one by one.

Further how I can make this in serial mode, or this we keep on using it?

I tried to define it in

serial as follows however approvals are failing to pick (I have attached the diagnostic log for your reference)