burning cd's using the imac (clueless in brooklyn)

i wonder if someone could please walk me thru the process of taking my downloaded mps's off of my hard drive and burning them to a cd. can i use the imac's disk drive to do it directly? do i have to get any software in addition to limewire, or attach anything to the imac? do the songs have to go to itunes first and than to a cd? if so, how do you get the music from the harddrive into itunes and than from itunes onto the cd?

thank you very much,
carolyn k.