Typically if you are ordering these and hatching them directly you won't need to do anything for them. If you feel that the cage you are placing them in or the substrate they came in is bone dry, rather than adding the water directly to their substrate you might find it safer to add a touch of moisture to a bit of paper towel that is in the hatch cage near them rather than trying to moisten them directly. They really only need the tiniest bit of moisture and that tends to be more important for storing in the fridge, rather than when you are hatching them out directly after buying. I would be careful about placing them in front of a heater or heat light because those can dry them completely out.