en_tn_lite_do_not_use/gen/06/16.md

a roof for the ark

This was probably a peaked or slanted roof. Its purpose was to protect everything in the ark from the rain.

cubit

See how you translated this in Genesis 6:13.

a lower, a second, and a third deck

This can be translated as "a lower deck, a middle deck, and an upper deck" or "three decks inside" (UDB) or "three levels."

deck

This can be translated as "floor" or "story" or "level" or "room."

Listen

This can be translated as "Pay attention" or "Listen to what I am saying." God said this in order to emphasize that he would do what he was about to say.

all flesh that has in it the breath of life

"everything that lives" (UDB). The phrase "that has in it the breath of life" is a figurative way of saying "that lives." (See: rc://en/ta/man/translate/figs-metonymy)