You should have putty (see putty.org) somewhere, It saves some typing because you can copypaste things.
Get the latest Debian 7 installation image, burn it or use a virtual machine (2 GB RAM, ~20 GB HD. Bridged Networking Adapter (Netzwerkbrücke))
Accept defaults, you may select a German environment.
Give your server a name, probably something more useful than exampleserver.
Choose a domainname, as long as you do not have one “localnet” is just fine.
Enter a password for root and confirm it, same for a user, I will take “www”.
Partitioning the harddisk, put it all in one.
Remove installation disk. Select a network mirror (use defaults)
We do a small install, just the system tools plus SSH server.
wait some seconds, or press <Enter>
At this point I find it more convenient to use putty than the console itself. Of course: if your main system is *nix, use ssh.
Log in, type ifconfig and get the IP number associated with eth0:
It should be sufficient to enter the name of the server (provided it used DHCP (default) on startup). You my of course you can use the IP number found above.
Confirm the fingerprint on first connection, …
And get a login:
Log in and update your system