How do I make a Linux Boot Disk?

I recently put the ISO of a FreeBSD bootdisk onto a CD... Only one problem, though... Windows boots up when i have FreeBSD in the CD drive. What did I do wrong?

1.) Make sure you burned it as an ISO file/disc image, not just the data.

2.) If that's all confirmed, go into your BIOS and make sure that CD-ROM is higher on the boot priority than HDD.

3.) If you didn't know this already, are you sure you want to install FreeBSD? You know, of course, that it will delete Windows and all of your data, right...?