If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You are required to detonate group of 3 and more blocks of the same color located in one row or diagonal. The bigger group the bigger amount of points and bonuses you'll get. After full demolition of those blocks all blocks which don't have the prop are falling down. Groups are created of flying from the top blocks and bombs combined in random order.