A primary source is a direct source of information. Articles reporting on a study that was directly conducted by the authors may be considered primary sources, as the researchers are reporting more or less directly to you without others' interpretations getting in between.
A secondary source is a mediated or interpreted source of information. Meta-analyses, for instance, pool the results of many different individual studies and view the different conclusions in relation to each other to make broad conclusions and observations based on a very large number of results.
To determine what kind of source you have on your screen, look for a Methods section. Was the research done in a lab, in the field, or by direct communication with subjects? If so, you probably have a primary source. If the research was done in libraries or databases, it is a secondary source.
Notice that even primary sources usually summarize the existing literature that relates to the topic before describing the study that was conducted. This is typically called a literature review or review of the research.
