Ground wire for add a fuse

Apologies if this is in the wrong area.

I'm installing a USB port in the left console/cubbyhole area blank switch. I'm doing it through an add a fuse. I understand how the add a fuse works. However, where does the ground wire from the new usb port go? Do I have to attach it to a metal piece or is there an easier way?

 

Look around near the fuse box and you'll find a couple bolts and nuts---just attach to that. Thats what I did for my radar hardwire

 

Thanks!

Did you have to solder it on there or is there a simpler way.

*edit* nvm, i'm such a noob, i just wrapped the wire around the screw and screwed it back in. Covered it with electrical tape.