I tell all my VMs that they have like 500G each... I have nowhere near that much space... I hope they don't all try to cash it in. I just built my Arch Linux one: https://wiki.archlinux.org/index.php/Beginners%27_Guide
is a helpful walk through to get everything you need. I still haven't managed to get Debian Stable to upgrade to testing/unstable without breaking.
Sidenote: <Host + T> is a print screen in VirtualBox