You need some media to boot SliTaz from, whether it be a tiny kick-start type CD to boot SLiTaz over the Internet from http://boot.slitaz.org/ or a CD-ROM with v3 proper. You can make a USB version from the LiveCD if you can find a computer with both connections, or use software like Unetbootin to create one from Windows or another Linux distro.
(If you have another (Linux preferably) computer, you could do as I did and set-up network booting, which is basically the Web Boot but over just your network -- that's quite an effort though!)