The admiral just points out in the distance
Well, first we hope and pray we get reports soon. Knowledge of our enemy will be very vital in making preparations. It would be awful if we invest time and energy into one defense that won't be needed, when another would have been a better use of time. But until we get a report, for now we make general preparations. Set up a few choke points, lay some traps in vital areas, set up barricades in other areas to try to steer the enemy hordes into the chokepoints, etc. If we are truly lucky, these men will make the blunder of thinking they have won the battle already. And when they come into the port expecting us to kneel, they will be all the more shocked when we blast them with muskets and cannon fire.