So the questions presented were concerning: The counting of the Omer? And is Shabbat at night?
Take the last first. A day, any day, starts at dark and ends at dark. First there was darkness and then there was light. Paraphrased. Okay the real text.
“Genesis 1:3 And God said: ‘Let there be light.’ And there was light. {So dark first, then Light.} 4 And God saw the light, that it was good; and God divided the light from the darkness.
5 And God called the light Day, and the darkness He called Night. And there was evening and there […]