The copy becomes a floating selection, which seems to hover above the main image. You can move a floating selection, or you can select the Transform tool to scale or rotate the floating selection.
Click outside the floating selection to deselect it. The selection’s content is pasted into the image, replacing the pixels that were below it.
Click in the floating selection with either the Marquee or Transform tool and Alt-drag (Windows) or Option-drag (Mac OS) to make another copy. Once copied, the original floating selection is deselected and replaces the pixels that were below it.