I think what lizardlady is referring to is the division of time seems a little arbitrary. Say we start with the premise a year is the time the Earth travels around the sun. Also during that time it takes more or less 365 rotations of the earth, so it makes sense to break the year down into 365 days.

Then consider that each day is a 360 degree rotation of the Earth. Why they chose to split that 360 into 24 hours I have no clue. Maybe making their sundials they found points every 15 degrees going around most practical, and 360/15=24? During equinox, there is more or less half of that rotation at the equator being day/the other half night. So splitting that 24 evenly into the 12 hours we have on today's clocks is more obvious.

Beyond that, they probably just used base60 math and split an hour into 60 minutes, and a minute into 60 seconds.

So basically 60s=1min, 60min=1hour, 1hour=15degree rotation, 1 day=360degree rotation, 360degree rotation/15degree rotation=24 evenly spaced points on a circle (24hr clock)=24hours=1day, 365rotations of the Earth or 365 days=1 year=one rotation around the Sun.