The United States and the Soviet Union along with other countries fighting for domination of international affairs. One of the most pressing issues of the Cold War was that of the growth of mass destruction weapons.
What was the Iron Curtain?
A barrier that separated communism from the rest of the European countries. Also, Joesph Stalin was the communist leader of the Soviet Union during the Cold War.
The Truman Doctrine and the Marshall Plan are kid of the same thing. The Marshall Plan was initiated to aid Great Britain after WWII and the Truman Doctrine was a program primarily to stop the Soviet Unions' geopolitical expansion during the Cold War.
Red Scare, Joseph Mcarthy, and McCarthyism
The Red Scare caused people like Joseph McCarthy to freak out about communist spy in America, which created McCarthyism. Joseph McCarthy was a senator.
The Space Race was the race between the United States to get a rocket to the moon. The hydrogen bomb was being tested in the Soviet Union and being produced after the United States dropped one on Japan.
Space Race and Hydrogen Bomb
Congratulations , you've learned a basic understanding of the Cold War.