What does your current program do? What have you been able to program so far? Can you get the leds to turn on?
In short what you will need to do is record the current position in the 16x16 grid. When a button is pressed, increment or decrement the position to move around the grid. If position 0,0 is the LED in the upper right, then increment on right and down, decrement on left or up. Then light up the new LED position.