Quick answer
Astrology works by combining repeated chart pieces.
A birth chart is built from a few kinds of symbols. Planets and points name the theme. Signs add tone or style. Houses show where that theme is placed in the chart. Aspects describe relationships between chart pieces, but beginners can save those for later.
That is the system behind the shorthand: planets are what is being described, signs add how it is expressed, and houses show where it lands. The shorthand helps only after the pieces are explained slowly.