I am very very new to this technology so please bear me out with the simple questions.

I have installed a 64k diginet line at my site and at the other site.
I have purchased 2 x 1841 Ciso routers one for me one for the other site.
I now need to setup and connect the two together and thats where it becomes grey and blurry.
The 1841 has a serial port connected to the NTU.
The other company has given me their ip address that my router on their side will connect to and told me to setup the router first and then ship it down to them.

So I need to know what needs to be done this side from IP addressing and Ethernet and serial setup.
The router also needs to NAT.

This is what info I have so far, I need to know what type of IP address range and subnets I should be using on the routers

My Company
Ethernet Cisco 1841
192.168.16.x Eth0 xxx.xxx.xxx
Ser0 xxx.xxx.xxx

External Company
Ethernet Switch Cisco 1841
192.168.17.x Eth0 xxx.xxx.xxx
Ser0 xxx.xxx.xxx