When you aiming for your first bird then you can use your finger,mouse or stylus to click. Drag the bird down & to the left side of the slingshot. Your '''bird''' will be released if you remove your finger or stylus from the screen.A correct aim will make the bird to travel over the columns as well as to hit the hill. You need to wait for a while to let the bird rolling down the hill and knocking over the uttermost right column. A domino effect will be created. As a result other columns will fall as well. If all pigs on the wall vanished then you can press the button on the right corner, which is marked with double arrow, indicates level is clear. You can use [http://wwwaskaboutpets.angrybirdshelpcom/index.organgry php?p=blogs/viewstory/438080 angry birds walkthrough] to know more about your levels.