opengl ,textures and 2d shapes

hello.
I'm creating a 2d interface in opengl with lines , rectangle and some other 2d shapes with qt.
I must have a background texture and the shapes on it.
I use vbo , shader ecc...
How i can positioning the lines and the shapes for appear on the background texture?
and what i can use for display the background texture?
i can create a textured plane for example with z = 0 and the shapes with z = 0.01 ecc...?
Is a correct approach?

thanks.