After you follow all instructions from last guide with success you can follow my final guide to Install SteamOS till finish.
1. Click "Start" button to boot virtual machine on virtualbox.
2. After that it will show a screen like screenshot below:
3. You must type FS0:\EFI\BOOT\BOOTX640 into the "2.0 Shell>" prompt, and press enter. After that it will show "error: prefix is not set" thing for a minute before GRUB actually comes up.
4. If success, you should choose "Automated Install" for begin installation like screenshot below:
5. You should wait installation till finish like screenshot below:
6. After installation finish you should click "continue" button to reboot.
7. After reboot it will show GRUB bootloader and you must choose "recovery mode" to enter to terminal session like screenshot below:
8. You should follow steps below to remove NVIDIA package and install vboxadditions:Instructions to remove nvidia package
a. Remove these packages with the command:
apt-get purge ".*nvidia.*"
b. Regenerate a new configuration file:
C. You can install vboxadditions package with next guideInstructions to install vboxadditions packageYou must install Vbox additions package with properly because very useful for x.org (the graphical engine) to work properly, as it contains the correct (video) drivers for the VM. Without it you'll just end up with a blank screen whenever you try to boot Steam OS.
a. Click "Devices-Insert Guest Additions CD Image" to mount Guest additions ISO via virtual box like this screenshot below:
b. Mount the CD-ROM to be able to access the contents.
mount /dev/cdrom /media/cdrom
c. Run the VBox additions installer, via the "sh" shell.
d. Reboot the computer.
9. After reboot you will back to GRUB bootloader and you must choose SteamOS not recovery mode again like screenshot below:
10. Finally, you only type "steam" for login and password to continue to SteamOS desktop like screenshot below:
11. Congratulations, you finish all my basic guide and you can use SteamOS desktop what do you like screenshot below: