﴿ فَإِذَا قَرَأْنَٰهُ فَٱتَّبِعْ قُرْءَانَهُۥ ﴾

“Thus, when We recite it, follow thou its wording [with all thy mind]:”

So when We recite it to you by means of Gabriel’s recital follow its recitation listen to its recitation thus the Prophet s would listen to it and then repeat it.