You get a certain number of clicks per level - click on a bubble, once it turns red it explodes hitting the neighbouring bubbles. Explode the bubbles in the right order to cause a cascade that wipes them all out before moving onto the next level.
After a bit of practice you'll learn the strategy for determining the best bubbles to click to get a win.
This game is highly addictive - be warned!
Our bubbles look like angry birds! :-)