First buy yourself either an iDevice or an Android devive
Go to the App store for iDevice if you have an Android go to the Amazon store. After that type in Graalonline Classic, it should be free.
Now that you have tapped install you should be able to play it.
You will be prompt to a screen advertising Era and Zone (Don't worry, Classic has been doing that every since they released since no one would of played it without Classic advertising). Click the invisible X, it will be on the top corner. And ta-da you are playing Graalonline Classic, 10x better than Era will ever be