As you conduct your search for secondary material, keep in mind the following questions to help you select high-quality and relevant resources:
See these resources for further information on evaluating secondary literature:
How to Read an Article Very Quickly
If the article is highly relevant, you'll then want to read it through, perhaps more than once. Scholarly articles tend to be pretty complex and it is normal to read and take notes more than once. Protip: taking notes and then writing a brief annotation will help you write your Resumen y Reacción papers as well as your final research paper.
Annotating is incredibly helpful, both for understanding a text and for synthesizing it and formulating a thoughtful response.