How to track my Ipod on find my Iphone?

My Ipod 5 got stolen at school last week. I went on Find my Iphone to track the Ipod and it worked and everything I made sure that when it was put in Wi-Fi it would play a sound, send a message, and lock it.

But I removed it because I didn't want to have the sound played anymore but now I don't now how to add my Ipod because it says I need my Ipod to it and that's pretty hard since I don't have it anymore. So is their away I can add it with out the Ipod?

You can't add it without the device.