To install any distro you have to make your system boot from Live CD or DVD that you created from an ISO file. On some computer system, they set it BIOS setting to boot from CD/DVD. If yours one like that, easy for you to install any distro cause it will automatically boot from Live CD/DVD. But not all system set like that, and maybe someone already change the setting. Then you need to know a little about BIOS setting in able to make your system booting from CD/DVD. If talking about installation in Windows by using Wubi, it is same concept to make the computer system boot from CD/DVD. If your BIOS setting not set to boot from CD/DVD, Wubi also will not work for you to install any distro from it.
Before you start all you need is user manual of your computer motherboard. In the manual you will find a key to push after you power on your computer in order to enter BIOS setting. So you need to search a topic about entering BIOS setup. Normally if non branded computer system, you need to push Delete key after power it on. After entering the BIOS menu, go to sub menu which is similar to "Advanced BIOS Features". Inside the sub menu you will find setting for boot sequence of your device. So you should select the first one to CD/DVD. If you use bootable USB Drive to install your distro, select it to the first boot order. Maybe you would not find USB Drive. It normally state as USB-HDD in your BIOS.
After set your boot order don't forget to save it. Then put your Live CD/DVD in your drive. Exit your BIOS then your PC should restart automatically and boot from you Live CD/DVD. Normally short cut to save BIOS setting and exit is push F10 on your keyboard. Select Yes then Enter.
Below picture is some example that I take. You can make it as a reference to make your system boot from CD/DVD.
01. An example to enter BIOS Setup.
Save your setting. Put your Live CD/DVD on it drive then Exit your BIOS Setting. Now you should able to boot from your Live CD/DVD.