What this chart shows
The blue outer ring shows ten planetary positions at the birth instant. The red inner ring shows the same ten bodies at the most recent exact New Moon before that instant. The New Moon is a conjunction of the moving Moon and Sun in geocentric ecliptic longitude. It is not the natal Moon, a lunar return, or a chart for the birth date copied into a second ring.
The birth place and recorded time make a natal Ascendant and house grid possible. The pre-natal New Moon happened at one worldwide instant, and this implementation does not assign it a separate local house grid. The comparison table therefore reports a birth house, while event positions remain house-free. The reading guide explains why that choice is made and how to read the two times.
For a single-ring view of the earlier phase, use the prenatal lunation chart. It can also show the preceding Full Moon or whichever phase was most recent; this two-ring selection always uses the preceding New Moon.