When building a Process Flow I often first think about from what "perspective" I want to build it. To decide this I try to answer the question: Who/What is making decisions? It could be a machine that is deciding what to process next or items that decide what machine to use to get processed.
In this case it makes sense to build the logic from the perspective of the operator, since it's generally easier to construct logic where a single token moves through a decision tree compared to many tokens competing for a set of resources.
To make this work, the 'operator token' needs a way to know if there are items waiting at the exit transfer, which can be done by pushing them to a list. (Lists are a powerful tool in general, especially when working with Process Flow. If you haven't done so yet, I would recommend you read up on them and work through the available tutorials.)
The logic is then structured into two loops, one where the queue is empty yet and one where it already has an item, with the token switching between these loops depending on the wwc label.
