Which DLC might you be referring to? Looking at the game history for your three characters, I do not see much game play after the initial launch months in 2017. Please note that the year one content, Red War, Curse of Osiris, and Warmind, was made free to all players. Though that same year one content will be vaulted as of 7pm Pacific, tomorrow, November 9th. If you are trying to access the story campaigns for the legacy content, you can visit Amanda in the Tower Hangar, to pickup those quests. Again, you will have limited time in which to complete those campaigns. If you purchased Forsaken while on Battle.net, and are not seeing that expansion on Steam; follow the instructions given by TheHaraamPolice.