Can i make a background after i made the level easily?

I have finished my level whit all the sprites that make up it. Now i want to add a background. The problem is that the newest sprites always overlays the older sprites. So if i now add a sprite as a background it will overlay anything else which removes its function as a background. I could add the background, remove everything and re add it. But that would be very time consuming. Is there a easier way to make a sprite be behind everything else. I tried changing layer but that makes the background invisible. Is there a easy way? There is probably a tutorial about this so you can link me to that too.

Add a new Layer, add a background, move it below the rest of your objects. Alternatively, you could manipulate the z-order of your objects using the z-order bar.