VMWare guest OS installs are virtual machines. They behave as though they are installed on a completely separate computer/environment.
When you create a new Vm in which to install the Guest OS, it asks whether you want the network connection to be bridged, NAT or shared/host.
Simplistically, bridged allows the Guest OS to appear to have it's own IP address, either from DHCP or static, connected to the local network subnet.
NAT is similar, but can do address translation, and shared uses the host computers IP address. All use the existing NIC on the host computer.
While experimenting, I would suggest bridged, which simply makes it appear like another machine on your local network.
I've never tried it, but I'm sure you could install a second NIC on the host, and use that for the VM's, but I've never found it necessary.