I am afraid, it will be difficult for you to get a ticket from August 11th on. Then the free online sales will start.It may happen that all tickets are gone already, purchased by club members.
I recommend to try over the commercial channels like Viagogo for a higher price.
Some are selling their tickets over this channel illegaly.
Thank you for your reply. I have posted my query in Deutsch again. The tickets on other platforms are too expensive. I am hoping someone who is a member or some regular fans could help another fan.