One of the banes of apps and extensions today is no documentation. So you have to ask the author or company. In this case I won't suggest looking for books since it's far too specific a request.
I am new to extensions and need to learn how to use them. I found a Chrome extension that searches for ads in Craigs List by using phone numbers. I go to the menu on my Google Chrome browser
and to more tools and extensions. The extension I want use is in a list of extensions. A note says it has been added I assume to the Google Chrome browser. What do I do now to start searching for ads in Craigs LIst using the phone number of the person who placed the ad?