Just choose which country you want and click the button. Pick whichever location is closest to you, or actually closest to where the content or service you are reaching sits -- for most people that is the same thing, but it is not always, and the account works the same regardless of which one you choose.
Trojan's password authentication carried over gRPC by Xray: the access check of Trojan with the multiplexed HTTP/2 transport of gRPC behind it.
