Dragon,
The red light goes on the left side, the green one on the right, when facing forward in the boat.
There are a number of ways to seal deck and hull. The simplest is to use epoxy if you think you won't have to get into the hull later. If you may have to be able to get into the hull later, a silicon type like used for automotive gaskets is an alternative. If you use silicon, surfaces have to be painted before it's applied, you can't paint over it. You can also use CA, which can later be 'broken' apart with a thin blade.
- LtDoc

PS - Before using the silicon, test it on a scap of the deck and hull material!