These editors are characterized by heavy use of the DEC Terminal keyboard layouts. For example, selecting text in TPU editors is always done with the "SELECT" key on the keyboard. Pasting is done with "INSERT HERE" key.
The EDT editor had an even more strange use of the keyboard that most PC users would be unfamiliar with. You need a Dec LK201 or LK401 keyboard. EdtKeyboardLayout.
To learn the details about those keyboards, check out this awesome site: http://vt100.net/
One very nice feature of these editors is the .JOU or JournalFile. This keeps you from losing any work.