Three placements do most of the work in a casual astrology conversation: Sun, Moon, and Rising. Together they're called your "big three," and knowing them is enough to follow almost anything else on this blog.
Sun is set by your birth date and describes your core identity — the version of you that's fairly constant across contexts. Moon is set by birth date and time, and describes your emotional interior: what you need to feel secure, how you process feelings when no one's watching. Rising is set by exact birth time and location, and describes the version of you that shows up in a first meeting — less "who you are," more "what people clock first."
Most people only know their Sun sign, which is a bit like knowing someone's job title and assuming you know them. Add the Moon and you get their emotional wiring. Add the Rising and you get how that wiring reaches other people. All three together is the minimum viable chart — everything else this blog covers builds on top of it.