The interface is designed to provide you with 3 things: a clear view of the board, information about the postition, and tools to help you learn and make the right moves.
Pretty self-explanatory! This where your lessons are displayed. You make the moves for your side (white or black); and the system responds with moves for the other side. The board also allows for highlighting pieces and squares should you use the assistance tools (see below).
Lesson Info & Hints
Immediately to the right of the chess-board, you can see information about the current lesson:
Just below that is a larger box-shaped text area: This is where the voice of your Mentor appears! Here you will read an introduction to each lesson and maybe pick up a few ideas about how to deal with the challenge.
As you begin the lesson, this area will show you the specific comments prompted by the moves you choose!
Immediately below the text box you can see the amount of time you've spent on this move, and on the entire lesson, so far. Your score for a given lesson can be affected by the amount of time you take to complete it!
Finally, near the bottom of the screen, you see the Hint box: If you're stuck, you might want to get a subtle (or not so subtle!) hint from your Mentor. Click on the hint button if you're stuck. Note, however, that viewing hints can affect your score for completing the problem. (See here for details on Chess Mentor's scoring system.)