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.
An SSH account is a login on the server itself: your device opens an SSH session and the rest of your traffic rides inside it, reaching the internet from the server's address rather than yours. The same login also works over OpenVPN and, on servers configured for it, over SlowDNS -- three separate ways in, so when one port is filtered you can switch path without creating another account.
