@codered: You should be able to change the selection with the trackwheel/ball or the T and G keys, and the move direction (arrow) with the space char. The game allows you to select only the pieces that can be moved (for simplicity and ease) and the directions in which the piece can be moved.

When you start the game, only one piece can be moved into one direction. The rest can't be moved so the game doesn't allow you to select them. Move that piece and see that after that you will have more options