Add W2k server to existing NT40 domain

School network has one existing Win NT40 server that also is the internet proxy server. We now have 40 Win 95 clients. We are adding 25 more computers and an additional Win 2K server. The plan is to use the new W2k server as the domain controller and the existing NT 40 server as the internet proxy and BDC. Should we install AD? What is the best procedure to get this mixed mode network operational? All the documentation I have found starts by upgrading the PDC to W2k. That is not what I want to do. Any help would be appreciated.