Primary sources are immediate, first-hand accounts of a topic, from people who had a direct connection with it. Newspapers, letters, diaries, government reports, images, etc., can all be considered primary sources. These sources are published and shared in a variety of ways. See below for some suggestions for finding primary sources:
In Catalyst, search for the person you are studying and include words like letters, diary, correspondence, interview, autobiograpphy, etc. as keywords
In Catalyst, search for the person you are studying. When the results appear, look to the left and scroll down to the category of filters called Genre/Form. Open this set of filters and look for terms that would point to a primary source.
On the open web search for the person you are studying and use some of the same words as above but also use words like archive or museum.