They were the formal writing system used in Ancient Egypt. They combine logographic, syllabic, and alphabetic elements. There are a total of 1,000 distinct characters.
They are written in rows and columns, and can be read from left to right or from right to left. How to recognize how to write? You can look at the human or animal figures, they always face towards the beginning of the line.
With that in mind, there are so many hieroglyphs secrets, and this documentary tries to discover them.