Decks can be exported to external file on the SD card either for backup or sharing. Browse to the folder you want it to be stored. Click on the the folder to visit that folder and click on the folder named .. to go upwards. Click on a file to place the name in the entry folder or type a new name in. Click on the button 'Save Deck' to start saving.
Before an existing file is overwritten, you are asked for confirmation, be carfull anyay.
As the storing could last a few seconds. Wait and watch the progress bar completing.