Q: How do I turn on home sharing on my new ipod touch?

Hello DavidAdamD,

Welcome to the Apple Support Communities!

From you question, I understand that you have a song on your iPod touch that you would like to move to the iTunes library on your computer so that you can use it in a slide show. If the song was purchased from iTunes, you can either transfer all purchases from your iPod directly to iTunes or simply download the song to your iTunes library on the computer. 

For more information on each of these processes, please refer to the attached articles below. 

Redownload or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer - Apple Support

Download past purchases from iTunes - Apple Support

Have a great day