Is there a design pattern for modelling a group of complex processes?

I've become responsible for a Java/Tomcat site that manages sales orders. It is largely a collection of static functions that happen to use objects for orders, customers, vendors and the like. I am looking for patterns for a replacement architecture.

My block to understanding things is that I don't have an overarching concept. I could say "This is an order processing factory, using instances of order, customer, etc.", but that seems to be merely a weak wrapper for a set of static functions.

I'm looking for links to discussions on how to define focused classes within complex processes. I already have database mapped classes for orders, etc. Can something like "validate order" really be a class?