Start realXtend Viewer (Note that there are some differences between the older client and the next-generation Naali viewer)
User Name: your accountname@authentication-server-address. If you are running a standalone server, you can connect with testuser@127.0.0.1. If you have registered an account in realXtend avatar service, it could be for example jackb@avatar.realxtend.net. Of if you are logging in to a LAN server, it could be jane@192.168.1.123
Password is your password
Valid connect to options are:
Authentication Server Home Grid - your home world defined on the authentication server by the server administrator (Not available in Naali)
Local Server - a server running on your local computer 127.0.0.1