how to add win2000 professional into NT

We are having existing nt network. I added one more machine in our network having windows 2000 Professional. I configured e-card and everything. Now i want to login to through network username and password. How can i add my machine to the my existing network. What exactly i want is, at the very first screen it’s asking username and passoword. i want domain name also. where i have to configure it.