Please refer to the context help (Get Help) which is available under Actions tab of each rule. This will provide you more information about each & every thing.

By the way, if you are getting error like page can't be displayed. Please follow the steps to enable the help

Designer Studio->System->Settings->URLs. In the first tab, we will be having online help url. 

Enter the url in the fromat. http://<<instance name>>:<<port number>>/prhelp.  Click on save. 

Now log off & login back. You will see the contextual help for each & every rule.

Hope this helps.

Thanks,Srinivas