Their trick is always to lay out the JW scenario of what the future holds, and back it up with what their translation of the Bible says. In many cases other translations contradict their version.
They love to show how scriptures "link up", so therefore they blend in texts from different books, including OT and NT. Much of that is a concoction that creates a fiction, albeit a convincing one. Armageddon is a perfect example: Rutherford knitted together unrelated scriptures in Ezekiel, Revelation, Matthew, Joel and others to build a picture of how the nations will do this, and God will do that.
Their "classes" are a similiar fiction: they use circular reasoning to explain why parables must "foreshadow" groups of people in later years: the "evil slave", the "faithful slave", the "John" class, and all these again simply reinforce pre-existing doctrines.
They are skilled at convincing people these complicated doctrines must be true .... and although you may not understand it now, well, just accept it and deal with it later. When it;s one householder against two JWs skilled at finding just the right scripture to back up their doctrine, it's hard to combat.