What did Stalin do to make Eastern Europe part of the soviet sphere of influence?

Stalin established Soviet control over Eastern Europe through a combination of military force, political manipulation, and the establishment of communist governments. After World War II, he installed pro-Soviet regimes in countries like Poland, Hungary, and Czechoslovakia, often using tactics such as rigged elections and suppression of dissent. The Red Army's presence in these nations solidified Soviet dominance and facilitated the spread of communism, effectively making Eastern Europe part of the Soviet sphere of influence. This process was formalized through agreements like the Warsaw Pact in 1955, which bound these nations to the USSR politically and militarily.