There are two ways to regulate volume on a MacBook. Mute and change it with the basic F10, F11 and F12 keys in the upper right corner of the keyboard. Alternatively, you can use the volume slide bar in the menu on the top of the screen. If you can’t see it, go to the Apple Menu → System Preferences → Sound. Tick the box next to Show volume in menu bar at the bottom of the window. If you want to change volume by less than one division, hold Shift + Option while pressing the volume change keys.