The reader would figure out which way to read it by the direction of the symbols.
The Egyptians are the second people after the Sumerians that invented the writing. Because of the complexity of the Egyptian writing, learning writing began at six or seven years, with only boys of the well-being class often sons of scribes.
The people who trained to write were called scribes. The bust of Nefertiti and the golden death mask of Tutankhamun both come from this era.
Taking their interpretation as fact instead of conjecture, Kircher insisted on an interpretation where each symbol represented a concept, much in the way the modern peace sign would be understood.
Besides writing and reading, the young scribes studied mathematics and architecture so that at the end of their studies they could also become intending, perceptive, treasurers, architects. Work on deciphering hieroglyphics with the help of the stone was delayed until the English defeated the French in the Napoleonic Wars and the stone was brought from Cairo to England.
But since there was never a purely alphabetic system, these signs were placed alongside other phonograms biliterals and triliterals and ideograms.
Every aspect of any of these creations had symbolic meaning. More economic power locally inspired more artists to produce works in their own style. This representation, apart from very special instances, was eventually rejected as an artistic form, the human face being shown only in profile.