I thought the one that turned the heated part on and off was green/white, but I could be wrong. I don't even have the car here to check. I followed the green/white wire off my heated rear screen back towards the fuse box and spliced it in there as close as I could to keep it tidy.
Earth the brown - obvious enough.
I just connected the power straight to the powered terminals on the fuse box. my mirrors are always live and work without the engine on.
From the looks of the ebay description you need to buy heated glass if you want them heated. this is expensive. probably why the auction was so cheap. Laying the loom can be tricky with the dash in. but you know me, I just take the dash out to do anything

the switch goes were the drivers side adjust use to live and you should have a grommet to go in the other side hole. good luck finding one if they didn't give you one. if your switch dies like mine did ones from passats plug straight in.