A:
You can, and the instructions are available on Page 7 of the manual.
For your convenience, we've included a copy of that here:
http://downloadcenter.samsung.com/content/UM/201204/20120404171145166/[UE4000-5000-ZX]BN68-04499D-00-ENG_web_0404.pdf
You can use either a USB drive with music, or an OTA-TV channel. Those are the only two inputs that you can use the Timer feature for.
Thanks for your interest in Samsung products. If we can help further, please reach out and let us know how we can help.
--Mr.Samsung