“How to read/understand this line: [Module.Order_Customer = '[%CurrentUser%]'], ”

What you can read here is the following:

“[“ this bracket starts the Xpath

“Module” – this is the name of the module that the entity “Order” is in

“Order_Customer” – This part shows an association between Order and Customer

“=” compares the contents of the association to a particular user

“'[%CurrentUser%]'” – The currently logged in user

“]” – Closes the Xpath