There are books that can help you learn how to read peer-reviewed journal articles and write your thesis . Here are a couple that I think are especially useful.
Abstract: summary of the article
Introduction: background information and a description of the author’s purpose
Materials & Methods: how the study was performed with enough detail so that other scientists could repeat the study
Results: includes new observations, data and findings
Discussion: a description of what the findings mean and their implications; address potential criticisms
First, skim the article. Read the abstract and skim the Introduction and Discussion.
Second, read and take notes. If you think the article will support your topic, then read the entire article. Be sure to take good notes.
If you can answer the following questions about the article, then you have a pretty good understanding of it.
There is no right way to take notes. You should find the method that works best for you. If you are unfamilar with note-taking methods, these are good places to start.