After you have run your searches, you will need to remove duplicates from your complete list of results. You can do this in EndNote - see Find Duplicates in the EndNote library guide. Then you need to screen the results to find the most rigorous and appropriate to help answer your research question.
The reviewing team
To reduce the risk of selection errors or bias, you should have at least two reviewers (including yourself) to screen your search results.
Two stages of screening
1. Title/Abstract screening: You need to scan the titles and abstracts to remove the obviously irrelevant studies. At this stage you might not need to provide a justification for your exclusions.
2. Full text screening: You need to locate the full text of the included studies and carefully examine each one for compliance with your eligibility criteria. The reviewers should document the reason for excluding any articles.
Your review paper should provide details of how many reviewers screened the articles and how any disagreements were resolved. This is usually in the Methods section.
For more information go to The Cochrane Handbook - Part 2, Chapter 4.6 (Selecting studies)