How did world war ii lead to the beginning of the cold war answers?

Before the United States dropped the atomic bombs on Hiroshima and Nagasaki, Stalin knew that the US was developing some sort of mass destruction weapon, but he didn't quite know the specific details. Once the bombs were dropped, and the Soviets stole the secrets to making an atomic bomb, both the US and the USSR escalated into a nuclear arms race, intensifying the already rocky relationship between the worlds two superpowers. Additionally, the rise of communism in several nations (Korea, China, Vietnam) scared the Americans into sponsoring civil wars in both Korea and Vietnam to try and "contain" communism, while the Soviets sought to expand their communist market into nearby nations. Americans saw this as the Soviets attempting to destroy capitalist markets and ruin the American economy, while the Americans saw Soviet expansion into Eastern Europe as a form of tyranny.