en_tn/gen/01/19.md

And there was evening and there was morning

This refers to the whole day. The writer speaks of the whole day as if it were these two parts. In the Jewish culture, a day begins when the sun sets. See how you translated this in Genesis 1:5. (See: rc://en/ta/man/jit/figs-merism)

the fourth day

This refers to the fourth day that the universe existed. See how you translated "the first day" in Genesis 1:5 and decide if you should translate this the same way.