Last required setup setup : User permission (since VPN-server runs ONLY on Windows NT, we need to handle the NT security issues).
Start up in the "Administrative Tools" the "User Manager":

Define for the users, that they are allowed to Dialin.

Everything is setup, now we need to start up the RAS to allow incoming calls:

We do that manually by starting Remote Access Admin:

RAS is NOT YET running, we need to start it:

It take a few seconds to start:

and then we are running:

Double-click on the listed server to see the status of the connections.

You can use the "Services" applet in the Control-Panel to start up RAS Automatically on booting up the system (avoiding to start RAS on each reboot manually).

Now, I am ready to connect my system to the Internet by dialing OUT
on the Modem:

I get my IP-address, which I then can use on other system to connect via the Internet to my VPN-server:

Here is the incoming VPN-connection using NetBEUI via the Internet.