By default virtual box uses internal NAT to connect the virtual machine to your network which is fine but I prefer to use bridged mode since it will expose the virtual machine directly to your network and give it an IP address via DHCP.
To configure the network for bridge mode just click on the network tab from the virtual box manager and the following screen will open
and if you hit the advanced tab you can see the type of adapter being presented to the virtual machine. If you hit the pull down under attached to and select bridged adapter and make sure you have the correct adapter shown in the name box should you have multiple network cards in your system.
At this point hit ok and we will be almost ready to start the installation. You will see though that there are a number of other settings that are available for the virtual machine. For the purpose of this article we will be using the defaults and I will cover everything you can do with virtual box in a follow on article.