In order to install Linux on your pc you will need an application to make your usb thumb drive bootable.
If you are using your "Windows" operating system you will need to download the "Rufus" application from here:
Once the application is installed launch it, select the usb drive and then select the .iso image on your system that you want Rufus to copy to your thumb drive. The program will show you the progress at the bottom of the app.
If you want to start the Linux install as soon as Rufus finishes leave the usb thumb drive plugged in and reboot ***BUT*** when you reboot go into your BIOS and go into the 'Boot Section' and make that usb thumb drive is the first in the boot list.
Once that thumb drive is first in the boot list 'Save and Exit' the BIOS. Upon exiting the BIOS your pc will reboot and should boot directly into the Live boot that Rufus prepared for you.
Follow the on screen instructions to install Linux.
When the installation is finishes it should tell you to reboot.
There is a short period when the pc goes down just before it reboots. BE SURE to remove the usb thumb drive just before it reboots.
***Otherwise*** it will start the installation all over again.
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Now if you are running a Linux distribution on your pc you can download
balenaEtcher .
<Or> you can check in your Software Center to see if your distro already has an app to make your thumb drive bootable.
Ubuntu has an app called 'Startup Disk Creator' that will do the same task.
Linux Mint has it's own usb app for that.
Select the usb thumb drive and the Linux .iso in the application program and wait for the program to finish.
Once Etcher or another application program that you use finishes the task of making your thumb drive bootable with the Linux .iso of your choice, reboot.
As soon as your pc reboots go into the BIOS to the 'Boot Section' and be certain that your thumb drive is first in the boot list. 'Save and Exit' the BIOS.
Upon rebooting your pc should boot into the thumb drive and start your Linux install. When the installation is complete reboot.
***BE SURE*** to unplug your thumb drive before the pc reboots.
If you forget to remove the thumb drive the install will start all over again.
If you had to you could hold the power button down wait until the pc is completly shut down and then unplug the thumb drive. Then reboot-