Congrats on your first rig and welcome!
Make sure to have some paper and a pen/pencil on the counter to write needed things down as you think of them!!!
Chances are the included starter kit is not the best. If you need help selecting some better quality items, we will be glad to offer suggestions and help spend some money!!!
Hauling water, as mentioned adds a fair amount of weight. I would suggest filling at the cg If your fresh tank is behind the axle(s). Reason being is to much weight behind the axle(s) can lighten the tw (tongue weight) to much, which can cause sway as a result.