They will be assigned separate IP addresses by the router (if you follow my previous answer).
In order to network the two computers, once they are connected to the router you need to run the Windows Networking Wizard. You should temporarily disable firewalls on both machines. Right click on folders you wish to share and enable sharing. Make a written note of each computer name (Control Panel, System, Computer Name) and click My Network Places and Add a Network Place. Follow the prompts. It can take a little time and Add Network Places seems a little truculent at times.
Eventually you get there.
It may help to use Search, Computers or People.
Personally I would do all the above with the computers connected by ethernet cable to the router just to avoid complications. Then get them to connect wirelessly (again temporarily disabling firewalls).