Please purchase a ticket for the concert, and you can get the meeting ID after July 1.
(The video message from Mr. Gunnar Jinmei Linder)
Ticket is available in following tickets sites, of course we will accept your application via e-mail.
https://passmarket.yahoo.co.jp/event/show/detail/01ctmd1118txq.html (required Yahoo ID, credit cards which issued outside Japan are available)
Each Tickets sites are available until JST15:00, CET 8:00.