An annotation is your summary of a research article. It is about one paragraph long, and writing annotations is an excellent way to prepare to write your literature review and discuss articles with your group.
Your annotation should contain key information about the methodology and results of the research.
What was the study about? What did the researchers find?
After that, include your own notes about the article.
How does this relate to my group's topic? Was there something surprising, or something I don't understand?