The developer view of the workflow describes the conditions to determine the various document states and how each process should be handled. To understand a workflow, it is important to recognize exactly what a workflow can accomplish in Odoo.
In Odoo, a workflow can:
Odoo also provides a very nice visual workflow designer that allows you to both analyze workflows, as well as make some limited modifications. I am specifically stating limited modifications as you are likely to need to have at least some experience in Odoo development if you are going to make anything but minor changes to workflows.