virtualbox internal connection

Hey guys,

so I want to finally set up my home virtual environment.. basically just a Windows server machine and a client Windows 7. I tried to do it couple of times already, but after setting up the server I failed to connect the two machines.

Now I have a clean install of both, the server doesn't have any DNS, DHCP - anything.
Before I install all of this, I want to make sure I have it right - because as I mentioned, I failed a couple of times before and I need to get it right this time.

I get my default internet connection from a home router into my notebook, so both the machines have exactly the same ip config.
http://i62.tinypic.com/2lazlh2.jpg
http://i60.tinypic.com/e0iowi.jpg

Both have a dual network cards, one to external to receive WAN connection and one internal, to communicate between each other.
http://i61.tinypic.com/286wnck.jpg
http://i57.tinypic.com/2im6m8x.jpg


Now my question is - when installing the server, do I need to enter any specific IPs (for the domain for example) and configuration? In my previous attempts, I just entered randomly some stuff...the server alone worked, but I wasn't able to ping it nor connect to it via the client.

Thanks for help.