Virtuabox

Extension pack

Download on the toplevel OS running Virtualbox (host) and double-click it

Network

There are many ways to setup ssh access to/from your VM. One very easy way is the second answer to this stackoverflow question [1], ie, Settings, set to bridged. Then your VM do ifconfig to know the IP. Install openssh-server on the guest.

Shared folders

Make sure to install the extension pack. Go to Settings->Shared folders I use

~/mnt/share

on both machines to share.