I am working in OpenGL ES 2.0.

Now I am writing a demo for my project,
I load two png images as my textures with the libSOIL

But now I need to use one of them as the texture of my demo's background
and another one as the texture of a rotating cube.

In OpenGL ES 2.0, the adding texture operation is in the shader

But now I don't know how to add the different textures to the different place in a shader

Who can help me!
Thank you very much!