I've written an extensive, step-by-step tutorial to installing and configuring Windows 8 (or windows 8.1) and Ubuntu (14.04 Trusty Tahr) in a dual-boot, side-by-side configuration on a real, production machine - Asus VivoBook (Ultrabook) with UEFI, Secure Boot and GPT, including preliminary reading and preparation steps, Windows 8 installation, Ubuntu installation, hardware setup, disk and partition layout change, resizing, shrinking and creation of new partitions, bootloader setup, tests in both operating systems, additional tips and tricks on data backup, system imaging, recovery, GRUB, GParted, Clonezilla, and more. Enjoy.