How do I make a background after i made the level?

There is tutorials about making backgrounds and such but in these tutorials the background is made before the level. Sprites visibility over eachother is determined by when they are added in the layout. The sprites who have been added the latest overlays the sprites that have been added before them. My background is the latest sprite so it will overlay anything else. You can make a previously added sprite overlay a later added one if you copy it, delete it and paste it back into the layout. Since i have added alot of sprites in my layout and now want to add a background it would mean that i would need to do that whit every single sprite in my layout. I tried adding the background to a lower layer but that only makes it invisible. Is there any way to change a sprites visiblity over other ones in a easier way?

So first of all, in the future get all your layers in place from the begining, start from the ground up, and if you don't have all your graphic assets in the begining at least use place holder graphs.

As to your current situation after you select add layer at bottom and you put your background in it, go to the layers above and set their property transparent to yes. That Should get everything to display properly.