Short answers, pulled from the story.
Arthur C. Clarke published the article titled Extraterrestrial Relays in October 1945 within the British magazine Wireless World. The piece described how artificial satellites could orbit Earth to relay radio signals back to distant points on the ground.
The first practical step occurred on the 4th of October 1957 when Sputnik 1 entered orbit. This Soviet satellite carried a radio transmitter operating at frequencies of 20.005 and 40.002 MHz and marked the beginning of the Space Age.
Intelsat 1 also known as Early Bird became the first commercial communications satellite placed in geosynchronous orbit on the 6th of April 1965. It provided multi-destination service carrying video audio and data to ships at sea.
Geostationary satellites orbit approximately 35,786 kilometers above Earth's surface directly above the equator. Their orbital period matches Earth's rotation rate exactly so they appear stationary in the sky to ground observers.
Russia launched its first Molniya satellite on the 23rd of April 1965 as part of the Molniya program. The first Molniya satellite enabled experimental television transmissions from Moscow to Siberian cities like Norilsk and Vladivostok.