Click once on the grey screen to begin.
Beneath the play button is a button to change the level of difficulty between easy, medium and hard.
You will then be asked to choose a puzzle.
Once you begin, your objective, of course, is to move the puzzle pieces (by dragging with mouse or finger) to their proper place.
In easy and medium difficulties, you only need to move the puzzle piece to its place. In HARD mode, you'll need to rotate them the right way as well!
