How to Dual Boot a Compatible Linux Distro with Windows 8

Method 1 of 2:

Assuming you have a Windows 8 PC or laptop and an Ubuntu 64-bit (or other 64-bit Distro) disk or USB ready, create a backup of your Windows 8 Installation just in case.
Create a partition where you will install Linux using Windows Disk management.
If you want to install an Ubuntu system in one partition and the files and folders in another, create 2 partitions, one about 30GB (but at least 15GB), and the other for your files and folders. The partition for your files and folders can be as large as you like.
You're almost ready to start the installation. The next few steps are where things may differ, depending on the PC.
Enter your BIOS settings to change a few things.
Find, and disable Fastboot.
Find the UEFI settings (in boot section of BIOS settings) and change the settings to allow "other OS" to boot.
1. Make sure that you do this correctly.

Method 2 of 2:

In boot options in your BIOS, find and select the Ubuntu UEFI option to boot. If you don't do this, the Ubuntu installation will not boot.
Using your Ubuntu DVD or USB, start the installation process.
When you've reached the options screen, choose the "something else" option.
Find the empty space you created in Windows.
Create a swap partition. Choose the empty space and create a partition that is equal to your RAM (the swap partition is named swap).
Create a root partition. This will hold your Ubuntu systems' files' application data, so make at least 15GB, but 30GB is an ideal size imo (the root partition is named ./).
Create a partition for your files and folders with the empty space left over on the created partition (this partition is named /Home).
Click on the partition you create for the System (./) and install Ubuntu. Upon reboot, if all was done correctly, you will get the grub screen.

Update 04 March 2020

You should read it