When you start the EV3 with a leJOS SD card in the card reader, the Start-up Menu Java program runs automatically:
The first screen you see is the Run Default screen:
There are a set of top-level menu items that you navigate between using the Left and Right keys. To select a menu item press Enter. To go back to the top-level menu screen, press the Escape key. When a top-level screen is displayed, Escape will prompt you to shut down the EV3.