Once the game loads all you have to do is click on any tile for the character to walk.
If you click on the rocky texture, the player will not be able to walk there and will stay in its current position. Also you will have to wait ~1 second after the player finishes walking in order to walk again.
This is a basic implementation of the A* algorithm and the game really serves no other purpose then to represent how the algorithm generates a path from the players current position to the tile you clicked on.