Scientific atlanta router epc2203 how to

Router: Thomson ST780 WL and Cable Modem Scientific Atlanta EPC2203?

Hi Guys,

I want to connect my Thomson ST780 WL router to the Scientific Atlanta EPC2203 cable modem.
So Rheinsequence: 3 PCs on router and router on cable modem.
Modem Atlanta has only one RJ-45 connector. Now I have connected this port to an Ethernet port on the router. Unfortunately the connection doesn't work.
The router probably does not understand that it should work as a switch and no longer as an ADSL router / modem.

Obviously it is somehow telling the router that it should use one of these 4 LAN connections as a WAN port. Maybe you have to deactivate the ADSL modem inside the Thomson router.
These are loud guesses from me! I am open to objective suggestions.

Now I have found on the Thomson website how to turn one of these Ethernet LAN connections into a WAN port.
How do I get on the router to enter the commands.
My operating system: Vista Home
Of course I know PuTTy and how to set up an ssh connection with putty.
I installed PuTTy and unfortunately I can't get to the router.
When I enter ipconfig into the Windows Console, it gives me this:

Ethernet adapter LAN connection:

Connection-specific DNS suffix: lan
Link-local IPv6 address. : fe80 :: dd66: 1a7a: 7913: d43b% 8
IPv4 address. . . . . . . . . . :
Subnet mask. . . . . . . . . . :
Standard gateway. . . . . . . . . :

Now I enter the following address in putty under Host. The port is set to 22 by default.
The following error message comes back:
Network error: Connection timed out

What am I doing wrong?
1. How do I create a connection to the router?
Further question:
Do you connect the cable modem to the router using a patch or crossover cable?

Thanks for help and best regards