1) Boot into Arch Linux in Virtual Box and click Devices > Install Guest Additions in menu.
2) type sudo mount /dev/cdrom /media/cd/
3) if you are not a sudoer then type su and type root password and then type nano /etc/sudoers
4) Under the User Privilege specification you can see
root ALL=(ALL) ALL
5) under the above option add similar time but replace “root” with your “name” then save the file and logout from the root mode
6) type cd /media/cd
7) sudo ./VBoxLinuxAdditions-x86.run
