Inspiron 3647 Boot Order

Hi ajfan1999,

Please follow the steps mentioned below to boot the system through optical drive.

1. Turn on or restart the computer.
2. Immediately at the Dell logo screen, starting tapping the key once a second until the One Time Boot menu appears (if the computer boots to Windows turn the computer off and try again).
3. At the One Time Boot menu, press the arrow key to highlight CD/DVD option to boot the system one time through the optical drive.

I got a Dell inspiron 3647 and the f-12 boot menu does not have CD/DVD as a option in the alt boot menu.

What do I do???