I'm aware that the red army was stationed in eastern Europe following the second world war. Yet, this does not mean that the sovereignty of these states suddenly disappeared. I expect there to be (fierce) resistance to a foreign overlord attempting to establish itself. Or at the very least, a less than smooth transition of power. So, how did the USSR manage to establish dominance in all of those countries?
/u/true_new_troll described how this happened in Czechoslovakia very well in this thread just a few days ago.