What's the best way to learn about workflows? Book? Website? Video?

My company sent me to instructor-based online training, which was good. If you don't have access to NetSuite there's a lot on YouTube. If you do, go to SuiteAnswers and search for answer# 40560, "SuiteFlow Overview." You'll see this partway down the page: Tutorial Follow the steps in the tutorial to create a workflow based on an Opportunity record. Use the steps in the tutorial to become familiar with creating the basic elements of a workflow, including states, actions, transitions, and conditions. See Creating Your First Workflow.