Basic steps to burn a CD w/I-tunes

a. Launch I-tunes.
b. Create a "New Playlist" by clicking the new playlist button at the bottom left corner of the I-tunes window. Name the playist as desired.
c. Drag the audio files you want to burn to a CD into I-tunes' main playlist window.
d. Click "Burn CD" at the top right corner of the I-tunes window. The tray of your CD burner should open, and Itunes should request that you insert a blank CD. Do so, and continue burning the CD.

For more information on I-tunes, use the "Help Center" from I-tunes "help" menu.