From the device where you want to import the data, open the e-mail where you sent the backup file. Do a long press on the KMZ file attached and choose “Copy to PhotoPills”.
Open the app Dropbox (you can download it from the App Store) and find the backup file. Tap on the share button and choose “Open with…” and then “Copy to PhotoPills”.
Open the app Google Drive (you can download it from the App Store) and find the backup file. Tap the “more options” button (the one with a vertical line of 3 dots) and then choose “Send a copy” > “Open in” > “Copy to PhotoPills”.