Each block has a different personality, and different behaviour when you interact with them.
You, the four-armed piece. You can slide over any empty square, and can push some blocks directly. You'll find that you cannot directly move some things.
You move by using either the keyboard or the mouse. Slider is set up so movement is controled by the arrow keys (up arrow, move up, etc.), you can change this in the Preferences dialog box.
If you wish to move using the mouse, put the cursor in the area you want your piece to move, and click. Be sure you're close enough, clicks only count if you're within one movement square of your player. The cursor will change into a directional arrow or a pushing hand when you can click and move.
