How was the mystery of Egyptian hieroglyphs solved?

About two centuries ago, Egyptian hieroglyphs were read for the first time by the French scientist Jean Francois Champollion. The hieroglyphs were inscribed on a stone slab. Some of the text at the bottom of the slab was written in Greek letters. The story was about the Egyptian king Ptolemy 5. Above the Greek part, various arcs, hooks, dashes were drawn, and even higher people and animals with household items were drawn. Jean François found out that one part of the text is hieroglyphs, and the other is written in cursive. In 1822, Champollion appeared before colleagues at the Paris Academy, with a report on the deciphering of Egyptian hieroglyphs. When decrypting, he looked for letters in proper names, this helped him to read the entire document.