1. Log into your Mostad Marketing account at https://cloud.mostad.com/login/
2. Click on "Email Reporting"
3. Click on the number of recipients from your most recent newsletter
4. Click "Save as CSV file"
5. Follow the instructions in the guide here and upload your new CSV file that you just downloaded. Note that this list will only have the email addresses and not any other data. You will need to pull any other data you want from your tax software and add it to the file and then re-upload it.