en_tn/deu/29/01.md

These are the words that Yahweh commanded Moses to tell

This refers to words that Moses is about to speak.

in the land of Moab

This is on the east side of the Jordan where the Israelites were staying before they entered the land of Canaan. "while they were in the land of Moab"

words that were added to the covenant ... at Horeb

These additional commands were given to make Yahweh's covenant apply better to the people once they were settled in their new land. These new commands did not belong to a different covenant, but rather were additions to the original covenant.