To use the controller, set the IP address of your Roku on the back of the widget.
On the front, there are two modes (which you can toggle with the backtick key):
In this mode, the key bindings are setup as a remote. Arrow keys move around, < and > fast forward and rewind, space pauses / plays. 'b', 'i', 's', and 'h' command back, info, search, and home, respectively. The enter key selects the on screen item.
In this mode, keys (other than the backtick) are sent to the Roku directly. The enter key closes a text entry.
Note: The behavior of the enter key is different in control vs. keyboard mode! Hitting enter in Keyboard mode will not select the on screen item!