The first thing to do is burn the ISO image file to a CD. Before starting up Clonezilla Live afterward, you can tweak the BIOS in the boot options of your PC's CD
All versions of Clonezilla live support machine with legacy BIOS. If your machine comes with uEFI secure boot enabled, you have to use AMD64 version of (either Debian-based or Ubuntu-based) Clonezilla live.