Check area menu swld.

Also try swdm t-code as it has lot of examples.

WorkFlow in simple: The state of an object changes from one 
state to anather with Human activity.
There must Human Activity involved. 
Example from agent to operational manager to next higher 
manager.

Agents submits a paper to be approved by his operational 
manger.
Agents object state is being changed by his operation 
manager with some interface/GUI etc.