Call it primary, secondary and tertiary research; there are three ways to get information as background for your poetry. The first is from your own experiences. Second is from people with whom you actually speak. Third is getting information elsewhere including libraries and the Internet. The veracity of information on the Internet can be suspect, so know the trustworthiness of your sources. There is also something that might be termed quaternary research, usually called “making it up.” Your best bet is to stick with the first three for any serious works. If you are writing something that is not set in the “real” world, quaternary research is fine.