Yes, that's all.

If you create a new account in pidgin, you've to choose XMPP as the protocol

Username: Rasczack (example)
Domain/Server: gmail.com (sometimes googlemail.com, but that does depend on you google account)

Ressource: you can keep home if you want to.
(Ressources have the purpose to be able to distinguish multiple logins from each other. In Jabber you can log into the same account several times and give them different priorities: Home, work, mobile phone for instance)

local alias: this is only what is shown to yourself in conversation instead of the whole account name (bob instead of bob@gmail.com)

what's important is that you don't check the box wheter you'd like to create a new account on the server, as your account already exists.

This check-box is to register yourself on most of the dedicated jabber servers.