This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Both parameter and property are actually related to the ActionMapping rather than the Action.
See the Struts Catalog for an example of how to use the parameter attribute.
As for the property, you need to extend ActionMapping and define your custom property that matches the value specified in set-property. Then modify your Struts config to use the custom ActionMapping class instead of the default one. Use your custom property getter method to access the value.