It's pretty simple to set up. You first need to set a class for applying the image as a background. Then add specific classes for each icon. Then in your CSS you change the background position, height and width to match the location of each icon. Here is an example:
.icon {
background-image: url('path/to/image.png');
display: block;
}
.icon.sprite-right {
background-position: 0 0;
height: 10px; // You can change these for each sprite
width: 10px; // You can change these for each sprite
}
.icon.sprite-expanded {
background-position: -10px 0;
}
.icon.sprite-right:hover {
background-position: -20px 0;
}
.icon.sprite-expanded:hover {
background-position: -30px 0;
}
Then, as you add new sprites you simply adjust the position until you can see the icon and then adjust the height and width until you are not clipping the image.