Hi, not likely to be a fan belf as most fans are now electric but could drive alternator/power steering. Locate alternator (looks like an electric motor with wires coming out of back) will be held by 3 bolts. 2 are fixed whilst other runs in slot. undo one in slot, move alternator so as to be able to remove old belt, put on new, move alternator to tighten (belt must have small amount of flex in same) tighten bolt!
Strevs, September 2007