You just need to get the water out of the block an exhaust manifolds. You can either fill it up with antifreeze or do what I do for the two months I can't wakeboard, remove all water from the boat during the winter. See the winterizing post for draining the exhaust manifolds and the block WHICH MUST BE DONE before freezing temps. It can be done easily with hand tools in about 30 minutes, same with all other routine maintenance on this engine. PULL THE THERMOSTAT before things freeze, it's three 12 mm nuts (studded!) and a rubber reuseable gasket. On the front of the motor, see the posts. For the ballast, there should be a gate valve near the forward water input in front of the motor. Open it, water will drain out through gravity. You definitely want to drain you speedo water, disconnect the small plastic tubes on the transom from the black plastic pitot tubes. There is a 5/16 brass nut holding them on, finger tight. They are under the swim platform. Disconnect the bag in the trunk and pull it for the winter. It will last longer.
See the other post for where the thermostat housing is, and where the block drains are. Don't worry, we will take care of you, and you bought an awesome boat that you will have so much fun with!
Let us all know if you have any questions. I know that boat, it is in top shape

you will love it.