Hi neighbor! Welcome to the addiction! I would suggest running the WSM with the water pan on your first several cooks, just to get a feel of how the smoker works and operates. After that, try wrapping the water pan in foil (top and bottom of the water pan, no sand added) and see how much longer your charcoal will last. Ultimately, it's whichever way you feel more comfortable with. I like no water, Dave likes it with the water in the pan..there is no right or wrong way. Good luck, any questions, feel free to ask, this site is slammed full of great people that only want to help make each other make better BBQ!
Tim