To ensure the Circle Base is able to accurately generate your report, you will need to upload a properly formatted CSV file with a single column containing only email addresses and no header.
You can download a sample CSV populated with CEOs of famous companies from this page. These are just for illustration.
Once you have your CSV file, all you have to do is drag and drop it on the section of the app titled "Upload File" as seen below and your report will populate!
When you click Download Most Recent Analysis, you will get a corresponding CSV file with only the Opted Members remaining. You can then upload this to your CRM directly to update those contact properties!