Watch how collecting cards differs from claiming a connection, then follow one destination ticket from the hand to the map. Notice which information is public and which remains private. During the teach, show how the game ends as well as how a route is built.
Follow the sequence from drawing a tile to placing it, assigning a follower when permitted and resolving completed features. Watch how features connect across tile boundaries. A clear physical example is especially helpful when explaining why a space is already occupied.
Start by following one legal trick: the lead, the obligation to follow suit and the winning card. Then watch how a task changes the desired outcome. Communication rules deserve their own explanation, because unrestricted tactical discussion would remove a central part of the puzzle.