Windows 10 not allowing me to boot from the DVD drive

Hello Guys٫
I’m using windows 8.1 operating system on my PC, From yesterday
I was trying to install another Operating system (Windows 10) on my PC. In order to do so, I need to load the ISO on a DVD or a USB.
At the moment, I only have a DVD,
so I burned the ISO on the DVD and restarted it. When I got into my MoBo splash screen, I entered into the boot menu and selected DVD. Instead of booting from the DVD, it booted from my HDD which contains windows 10.

So, I changed the priority of the boot to DVD first. Still didn’t work. It just boots into windows 10.
When I was on Windows 8.1, it worked fine.
But it doesn’t work on windows 10۔
I shared about this type of issue with my friend, he also tried but we can’t find any issue. He is saying I think you should try from a USB drive…but currently, I’m using a DVD drive don’t have any USB drive.
Any ideas to solve this issue…?