So basically ive just started in unity and i found a tutorial to make a flappy bird clone (http://anwell.me/articles/unity3d-flappy-bird/) And basically my problem is when i downloaded the background to my textures folder and tried to add it to the scene it would show a circle with a across through it. Any answers appreciated. Thanks.

You can’t add a texture to a scene. You add a texture to a material, which is assigned to a gameObject.

If you click on the background image and then go to the inspecter and change the texture type to sprite (2d and ui) making sure you click apply, you should be able to then use it as your background image.