If you already have an AQ3D account, go to Battleon and talk to any Concert Promoter and you can get a concert ticket for free. You can use this ticket to teleport to the Battleon Travel Portal from anywhere in the game once it begins. This will teleport players to the concert map between concert runs.
If you don’t have an account, no problem. Create a free account and a ticket will automatically be added to your account - but complete the tutorial first, because this event will require some swords and sorcery.