Religiously observant Jews place mezuzot (pl) on every doorway in their house except for washroom doors.
A Mezuzah is a scroll with verses from the Torah hand written on it. They are located on every doorway in a Jewish home except for doors going into washrooms. The mezuzah is a daily reminder and declaration of Jewish faith. Please see the related link for a detailed explanation.
The Talmud describes a dispute regarding the proper placement of the Mezuzah whether it should be horizontal or vertical. As a compromise it's placed in between the two, on a slant.
They are placed on the inside of the right-side doorpost as you enter a room. It should be placed on the lower part of the top third of the doorpost so that it's around shoulder height and it should be placed on an angle so that the top of the mezuzah points toward the room being entered.
The mezuzah is not a reminder, but the fulfillment of a commandment or mitzvah - that found in Deuteronomy 6:9, which tell us to inscribe the words of the Sh'ma blessing upon the doorposts of our houses.
There are two parts of the Mezuzah, The Mezuzah Scroll itself and the Mezuzah Case. The Mezuzah Scroll is made with ink on parchment of a Kosher animal. The case can be made of almost any material as its purpose is to protect the scroll. Most common materials for the mezuzah case are metal, stone, wood and glass.
There is no limit to the size of a Mezuzah. Attached is a video of the largest known mezuzah recently installed at Ben Gurion Airport.
The scroll inside the mezuzah is written in Hebrew.
The origin of the mezuzah is from the "Shema" in which is mentioned the core beliefs of Judaism and its teachings. Therefore, the "purpose" of the mezuzah is as a reminder, when entering and leaving the home, of the mezuzah's message. The mezuzah contains a parchment inscribed with a passage from the Torah (from Deuteronomy ch.6 and ch.11), placed on Jewish doorposts.
An angle bead is a bead worked on or fixed to the angle of any architectural work, for example protecting the angle of a wall.
The proper way to hang a Mezuzah is on the right doorpost, when entering a room. It should be placed at the bottom of the top third of the doorpost height. It should be at a slight angle (about 15 degrees) facing inwards, towards the room. It should be installed using nails, screws, adhesive or other permanent installation method.
The Mezuzah was not "found". The Mezuzah is a Jewish ritual object whose origin is from the Torah, which dates back to 1313 BCE. I guess you could say it was found then.