Question [Q] Rooting Tab Model GT-7510, wi-fi only

New to forum and rooting devices. Just upgraded software to to Icecream 4.0.4 and now having trouble rooting my device.

Gets to the front screen then says "Downloading" & a warning "Do not turn off"

The top left hand corner the bottom line says "waiting USB cable"

I waited for about 3 hours and finally I took the plunge (heart in my mouth) and turned it off and re-booted and thankfully everything seems ok.

The problem is how do I get to root my device?

Cheers

Lionel in NZ