i'm sure there are more than two ways to comprehend it.
here's a second - that before the mean-free-path of an electron was greater than a planck length, there could be no such thing as light. this was evening. then He said "let there be light" and the universe inflated - and there was light. this was the first morning. then He separated the light from the darkness, space where there were photons and space where there was not, and called one Day and the other Night. this happened on the first yom.
on the second yom He cooled and expanded the superpressurized, superenergetic, superheated superfluid substance of the universe some more, which was as "waters" for lack of any better Aramaic word, to the point that it could exist as what we call 'ordinary matter' like atoms, and then further like gas and liquid. He separated these according to their kinds, into "waters above" called the heavens, and "waters below" and set gravity to work, so that there began to be such a thing called "up" and "down" and "above" and "below" -- and photons continued on their paths, and there was light and dark, evening and morning according to His cosmic measure, the second yom.
then he coalesced the planets, making solid things. He called this "Earth" - especially our planet. He put plant life on it and pooled up some of the gasses around it into liquid seas. He set it spinning so the photons hitting it weren't constant - so there was evening and morning. there was the third yom.
then we finally started to feel at home, when He placed us in our place with a sun and a moon, that we've been using together with our relative position to them ever since to measure a wibbly-wobbly thing called "time" -- and we had a thing to call evening on the earth, and a thing to call morning on the earth, and we finally had something proper to call a "day" -- that was the 4th yom.
the simplicity is that you can understand it from your place on your planet in this universe, wherever you find yourself.
the sublime thing is that even as your knowledge increases, it's still true.
JMHO.