You don't need to add a payment method. The ticket shows in the google pay wallet as per the photo shown in
@Elbow beards post.
If you click on the ticket it will then open showing your seat ticket details and a little image saying 'hold to reader'
You dont need to add payment details.
Once you have downloaded it will show the ticket in your wallet as per @Elbows Beard post.
If you click the ticket in your wallet it will show your seasoncard details and if you click on 'Details' it will show you the details of the next upcoming game.