Teams and fans can purchase tickets end event-shirts through the official LOC webpage:
The LOC recommends to buy tickets through this channel. The best seats in front of the competition mat are already sold out. So it will be not sure if there will be still tickets (or at least good tickets) available on the competition day.
LOC also announced to ECA that they will grant access to competitors to non-competition days free of charge. Subject of this policy to be determined and to be communicated by LOC.