The basics are really not that hard, you can "build" like in any puzzle game (the next block in line is shown on the bottom left side of the screen), and to remove a row, you need to put 2 blocks of the same colour (but different than the colour of the row) on each side of the row. Eg: you have 5 yellow blocks with a red one at one end, so you need to put a red blok at the other end of the row, a red line will now appear around that whole section & you can press the remove button if you like (should the 2 red blocks be blue blocks, a blue line will appear, same for all the other colours).
The tricky part is that you need to think in 3D because you can walk all over the place, and you can flip the puzzle in every direction with a button . And to make matters worse, you can play it 2 player against each other
It's an awesome game, very stimulating for the brain