How do I allocate Customer Numbers incrementally when creating new records in Zapier Tables

Hi

I want to add a new record to a Zapier Table every time I get a new customer in Shopify.  The record will include the basic details of the customer and also allocate it with a customer number.  The customer numbers will be incremental.

I think the Zap should work something like this:

Step 1 - Trigger - New Shopify Order

Step 2 - Action - Zapier Tables - Increment Step

Step 3 - Action - Zapier Tables - Create Record (mapping the value from Step 2 to a ‘Customer Number Field’).

However, I’m stuck at Step 2.  How do I lookup the record ID of the latest customer to be added (and thereby find the latest customer number allocated)?

If this is obvious, apologies, I just can’t see it.

Any help, much appreciated.

Christian