Before you start searching for primary sources, it is important to understand what a primary source is.
The primary sources that might be useful to you depend on your research question, so take some time to consider what sources you need. Common types include, but aren't limited to:
Interview transcripts
Diaries
Letters
News Footage
Speeches
Original creative works (poems, stories, novels, plays, etc.)
Once you have determined what you need, try searching your library or Google using terms that refer to that type of source. For example, if you are writing a paper on Barack Obama, you might search with the keywords 'Barack Obama interview'.
If you are looking for original creative works to study, like Margaret Atwood's novels, it can be useful to search by author. This will make sure that you find works created by the person themself, as opposed to works that are about them but written by someone else.
Can't find anything? Authors of secondary sources often cite primary sources. You can follow their citations to find primary sources about your person or topic.