There is not tutorial.
But I think you can understand rules immediately.
Postscription - 11/05/2014
It seems like I had wrong sense of this game.
Goal : Gravitate all blocks to same color floor icon.
1. You can click bright grid.
2. Then, [up,down,left,right] blocks are gravitated to your side.
3. Next, you can click grid where is connected floor (not exists blocks) with point of your clicked grid.
0. Grid that exists block is always disclickable.
Please imagine the Sokoban puzzle If you don't understand in my funny English.
Sokoban moves to your click grid.
And he uses GravityAbility there.