You can see three lists of articles. Please read each list comment and follow the instructions:
New articles means the articles newly assigned to be reviewed by you. These articles selected based on your specialty. You can download and study the article by clicking on download button. Then you may click on start button and begin the review process and filling the review form. Also if you feel you cannot review this article for each reason, you can click on cancel button to remove the article from the list.
This list consists of the articles that you have filled the review form for those, but you still did not complete this form. You can complete the review form or even change your previous view of points. Then when you complete the reviewing steps you can click on confirm button to move the articles to the third list.
This list shows the articles that have reviewed by you. The articles and related review form will remain in this list for 3 month. Since you confirmed your review, and journal management team used your comments for accepting or refusing the article, you cannot change your comments and answers in this step.