This is the first program in App Inventor. In this lab, we will learn how to use button and sound element. We need to create button and then add the picture on that button to change button to picture. Then, we need to add sound, which is invisible element. so we cant see it on app. after that, we need to use the block to set up our program. when the button1 is click, sound1 will play. Keep doing that, we will get the AppZoo with at least 4 animal button and sound on it.