To obtain an invitation, you must provide your Tezos address obtained during the fundraiser.
The XTZ public key hash is a 36 character alphanumeric string starting with tz1.
You will then obtain an invite link to the chat which will expire in two hours.
Because we do not keep track of user/address mappings, if you do not use your invitation within two hours it will expire and we won't be able to generate a new one for the given address.
Note: Your XTZ address is only used at sign-up, other users won't see it.