livfs

Hi,guys,i m downloading FreeBSD os through dis link ftp://ftp1.us.freebsd.org/pub/FreeBSD/releases/i386/ISO-IMAGES/7.0 .can u tell to me cd 1,cd2 cd3 nd cd doc is require?.mean wat is cd livfs nd is not require . and wat will i be do with dis both file "CHEKSUM.md5 & CHEKSUM.SHA256.plz help me bro