Basically you don’t need a tutorial to do it, but if you do need one, here’s a good one to follow:
The above post is from EverydayLinuxUser. Thanks btw.
I find some difference when I follow the post. First of all is the dual boot setting. Since I use an old Dell laptop and it’s running legacy BIOS, so I don’t have the fancy UEFI (if you don’t know what UEFI is, check its WiKi) to play around. But I find it lucky since you don’t need to worry about anything, and just install the Ubuntu like you don’t know about the UEFI exists. Once you complete the installation, you’ll notice the Ubuntu dual boot system (GRUB?) is working.
The second difference is about the partition issue. Before installing Ubuntu I shrink the partition and free up 40G space. During the installation I choose to install Ubuntu alongside the Windows 8.1, and after it is done everything works fine. Inside Ubuntu I notice it is already installed on the empty space. However I could be wrong since after I switch back to Windows 8.1 I notice the empty space is still there. I don’t have time to check it further. Maybe someone knows more and could tell me in comment.
Someone may want to know how to install Windows 8.1 on a Ubuntu 14.04 LTS or other version. That’s where I begin as well, but after a lengthy search on Google I don’t find much useful information, and notice there will be much trouble even if I did it, I give up by wiping the Ubuntu I have an install the Windows 8.1 first. It seems to be a missing piece for a good tutorial about it. If you notice one please let me know. Thanks~