A new moon is the moment the Moon catches up with the Sun and stands at the same degree of the zodiac. Nothing of it is lit from where we are standing, which is why the night sky is dark, and the whole cycle starts over roughly every 29.5 days.
Astrologers treat the new moon as the opening of that cycle and read the sign it falls in as the theme it opens with, which is where the habit of setting intentions on a new moon comes from. Because the Sun and the Moon share a degree here, the sign of the new moon is also the sign the Sun is in that day. The date, time and degree below come from Swiss Ephemeris; anything drawn from them about your own life is interpretation, and we say so instead of promising outcomes.