“Moses reported the words of the people to Yahweh.” Yahweh was on the top of Mount Sinai, and so this was Moses’ second trip up Mount Sinai, in which he brought the words of the people back to Yahweh. God gives Moses more instructions for the children of Israel, and Moses takes those instructions to Israel when he goes back down Mount Sinai on his second time down (Exod. 19:14).
[For more on Moses’ seven trips up and down Mount Sinai, see commentary on Exod. 19:3. For more on God speaking directly to Israel with a loud voice from the top of Mount Sinai, see commentary on Exodus 19:9.]