If you want to see what learning a one-handed keyboard looks like, here are links to tutorials that I know of. I haven’t used the BAT keyboard.
http://www.maltron.com/training/index.htm Tutorials for the Maltron left and right handed ergonomic keyboards.
http://www.brandonfla.com/typingtutor/download.htm Tutorials for the left and right handed Dvorak layout. Dated, but should work.
http://www.infogrip.com/bat_kybd_details.asp#documentation Tutorials for the left and right handed BAT chorded keyboard.