How to remove the background from a sprite?

Ive gone through the sprite tutorials and have looked at the flappy bird but I cannot seem to figure out how these tutorials were able to only use the sprite and not the atlas background around the sprite.

In other words, I animated my sprite but it has a white box around it. I can’t find any reference to this in the tutorials. Please help.

Hi, in the material used for your sprite you select opacity and put there the same texture used in diffuse, you change the channel (close the name of texture on the right) to A (alpha) and change the bar alpha test below to the point you obtain the right transparency.

If you look at the material used, you can see that the offset and tiling was changed to only use a small part of texture for the material.