When the station is on, open the main menu. Go to Tools > Backup and click with the center button. The screen will show the word "backup" while backing up the data.

The screen will then return to the header showing the station name. This time, go to Tools> Export CSV and click with the center button. The display will export the data in CSV format to the microSD card, and you can download it from the card when you bring it from the field.