Configuring Cisco 831 for Cable Internet Access on My LAN

Hello,

I have a Cisco 831 router my employer lent me to play around with.

I also have a LinkSys E4500 wireless router but for the moment I'd like to leave this out of the picture entirely just to say I configured a Cisco router via command line and got my Internet working.

Ethernet0
Ethernet1
FastEthernet1
FastEthernet2
FastEthernet3
FastEthernet4

What I don't understand is why there are two Ethernet ports showing:
Ethernet0
Ethernet1

I'm assuming one of these is the WAN that needs to be configured for DHCP as I'm on a Cable Internet connection but I'm not sure which one. Is 0 for the internal LAN and 1 for the WAN?

If so then I would do something like

conf t
interface Eth0
ip address 10.0.0.1 255.255.255.0
no shut
exit

interface Eth1
ip address dhcp
no shut
exit

I'm probably missing quite a bit.
Would NAT be enabled by default?
I heard something about the following two commands:

ip nat inside
ip nat outside

Are these at all relevant to what I need to do?
I've got a couple of desktops that I'd like to plug into the LAN ports and give Internet access to.

Thanks in advance for your help,

Alexander

The Ethernet0 is for LAN side but for WAN side, it can use different interface name dependent on WAN interface type.

Ethernet1 should be your outside interface which will grab an IP from your ISP via DHCP; Ethernet0 will be a virtual interface for the inside network which will become your gateway interface for all connected devices.