i believe you simply burn the iso to disc - as the iso should be bootable anyways. using nero - do not burn it as a data disc. cancel the wizard, go to the file menu, and choose burn image. it should be as easy as that.
whether you can boot from it is dependent on your system. you should change the boot order in your bios. if your system is incapable of booting from cdrom, you will have to boot to knoppix from dos
best of luck.