Remove the screws at the bottom edge of the windscreen. Remove the two screws in the ventilation air intake in the front.....plastic.....nose thingy. The triangle shaped opening.
The nose panel has a pair of plastic hooks that will want to keep it in place. They hook UPWARD, which means you need to move the piece DOWNWARD. Fiddle with it a bit and it will come off.
From there, removing the windscreen is a matter of taking out a few screws. It's easy.
To install the Givi correctly you'll need to use the two metal brackets they supply with the new windscreen. You'll need to drill a couple of holes in the bike. You're drilling through plastic, so use a slow drill speed and be careful. It's easy, though. Use a bit that is just slightly larger than the supplied screws you'll be using. On the inside of the piece you're drilling Honda has already attached a couple of nuts. Be careful not to damage the threads.
It's really a pretty easy install.