It's easy to get started with Automator, simply launch the application, and add the items you want to process to the beginning of the workflow in the Automator window.
For example, if you're working with Finder items, just drag them from the desktop into the workflow area and let go -- a new action will automatically be added that lists the items you added.
Select and Do
Another way to start a workflow with Finder items is to use the Finder's Contextual Menu. Click on selected Finder items with the Control key held down to summon the Finder's Contextual Menu. At the bottom of this menu is a sub-menu named "Automator." Choose "Create Workflow..." from the sub-menu and a new Automator window will open, displaying a workflow that begins with an action that lists the items that were selected in the Finder.
Find and Do
Automator draws on the power of Spotlight to help you find items for processing using not only file names, but also keywords and other metadata. Spotlight search result dialogs offer a contextual menu item that can create new Automator workflows with the selected items in the results window.
New workflows can also be created from Spotlight search results displayed in Finder windows: