Unfortunately, you cannot link your Steam account to your Wargaming.net ID account via World of Tanks—the game does not have a dual authorization system. When you log in via Steam, you will start playing with a new account.
World of Tanks was not originally developed as a multi-platform project.
If you already play the game, you should continue using the PC client.
If you log in to the game via Steam, it will automatically create an account that links to your Steam account.