Every time you export your cards, Covve Scan will export all the cards you scanned. If you are looking to select a specific group of cards, there's 2 ways to help you do that:
1- Date scanned
The CSV/Excel file, contains the 'date scanned' for each card. A quick sort of the CSV data in Excel by 'date scanned' will allow you to select only the card that you scanned during a specific period.
2- Using Tags
If for example you use Covve Scan to scan your business cards during a specific event, you can easily tag those cards with a custom Tag. This way, when you export the card data in CSV, you can easily sort/filter your data in Excel by Tag.