I assume you have a CD burner.
Get a blank CD from the left most happy space cabinet. Put it in the CD drive.
The CD will appear on the desktop with an icon that sez CD-R. You will be prompted to name the CD.
Double-click the CD to open its window. Drag your stuff to the CD, just like moving it to any other location. You'll get a copy box.
Once its copied, drag the CD-R icon to the trash. The Trash icon will change to a Burn icon.
You'll get a dialog that asks burn or cancel or something. Click burn.
After a few minutes the burn will finish and the CD-R icon will change to a regular CD icon. Drag this to the trash to eject it. You can also test the disk by opening it.
Label the disc. Always use a sharpie or other reliably-permanent marker to write on CDs.