Terms containing first things first

Subject	English	Spanish
gen.	first things first	lo primero es lo primero
gen.	he didn't know the first thing about the subject	no sabía ni jota del tema
gen.	he doesn't know the first thing about the subject	no tiene la menor noción del tema
gen.	I said the first thing that came into my head	contesté al voleo
gen.	it was cloudy first thing in the morning	amaneció nublado
gen.	mind you, I don't know the first thing about that	te advierto que yo sobre eso no tengo ni idea