I don't know that I could do a good pinning job on a carpet. I use a table or my kitchen floor. When using kitchen floor, I tape the backing to the floor in several places on each side making it a bit taut; add the batting smoothing it from center out with my hands; add the quilt top; & then start pinning. When using a table top of my sewing maching cabinet top, I use the binder clips & pin in sections.
When machine quilting with walking foot, I start in the center & work out.