Open iTunes by clicking on the iTunes icon on your desktop.
Click "+" in the lower left corner of the iTunes screen underneath the "Playlists" column. You will see a new playlist added titled "untitled playlist." Double-click on the new playlist to change the title.
Click on "Music" under "Library" to go to all your music.
Click on a song that you want to add to your mix, and then drag it on top of your play list and drop it. Repeat this step again until you have added all the music you want on your mix CD. Click on your playlist to see all the songs you have added.
Insert a blank CD into your CD drive. Click on your playlist and click "Burn." in the upper right corner. Eject the disc when it has finished burning.