I have now compiled enough information to make a very nice map of a lake in Ohio. I am using a Lowrance HDS Gen 2 / structure scan. I found a sunken boat that has a coordinate with it. How do I put this waypoint on my RM Map? Check out the image.

The easiest way is to view the sonar log in the track edit window sonar viewer, select the "drop pin" mouse mode and click within the sonar image. That'll get you a waypoint that placed directly on the course of the vessel, so if you went directly over the top of the feature (looks like you did) then that will be close enough.
The other alternative is to view the structure scan in the track window in mosaic mode (mosaic module required) and drop a waypoint in the map view.

Alternative three is to just drop a waypoint anywhere (again, put mouse in "drop pin" mode and then left click in the map view to drop a waypoint) and then edit the GPS coordinates in the new waypoint window.