Downloading a shared folder takes only one tap in ND1 (v1.3 and higher):
Be sure you have a connection to the Internet.
Go to My Data, Folders under Downloadables, and tap the folder of your choice.
You will now have the contents of that folder.
If you subsequently upload this folder (via Sharing | Upload), it will be tagged with your User ID and made your personal copy. You don't have to worry about overwriting the shared folder--you can't.