How to get to the Hotel Lux from Marco Polo Airport.
Do you plan on buying a vaporetto pass for you stay in Venice? If so you can add the No 5 bus to Piazzale Roma on to the pass when you buy it for 6 EUR each way. Othewise, it is a 14 EUR for the combined bus-boat ticket. Take the No 5 bus to Piazzale Roma, then board the No 1 vaporetto for a slow but scenic ride down the Grand Canal to San Zaccaria stop then walk back the alley to the left of the Danieli Hotel.
There is also the Alilaguna "B" boat to San Zaccaria for 15 EUR. Not really recommended due to crowded low seats in the boat and generally dirty, salt covered window, so not much of a view, and a lot of intermediate stops on the way.
Finally, private water taxi direct to San Zaccaria for about 120 EUR.
If this helps, go on the hotel web site, email the hotel and ask them how to get to their hotel and finally check google maps.
This may help to see it on google maps and see what the previous poster explains by using the map and his instructions.
Ann mentioned google maps. It will take some experimenting, but you should be able to use the street view to "walk" the route from the vap. dock to the hotel before you ever leave home.