Again, this is a basic research process, you may need to repeat steps at various times! That is not "bad" (or not doing it "right the first time")--that is thorough research!
Identify and define your topic. Put your research topic into a question such as, "How did the 1918 Influenza pandemic affect the military, particularly at Jefferson Barracks?" Now you can identify the main concepts and keywords, including alternate terms, for your topic.
Use overview sources to deepen your understanding and vocabulary around the topic. A subject specific encyclopedia or dictionary can help provide an overview of your topic while an overview database can help provide in depth overview articles that may suggest specific research paths. (Go ahead, check Wikipedia. Then come on back for the good shtuff!). Such sources can be in print in the library or available electronically via subscription databases.
Use specific individual databases to find magazine/journal/newspaper articles.
Use the library catalog and/or eBook databases to find monographs and other resources on the topic.
Search for reliable and authoritative open website resources. Try the librarian recommended websites on this guide.
Always evaluate the information that you find. Consider accuracy, authority, objectivity, timeliness, and use/purpose. Don't be afraid of opinion/biased resources--just be sure that you compare such a source to others from varied viewpoints/biases.
Cite your sources. Citing gives proper credit to the authors of materials you use and allows your professors to verify your conclusions. Your paper's credibility relies upon your use of credible sources!