Tinkerers are a specialized craft school associated with the Blacksmith, though all the Outfitter and the Scholar also give some of the skills needed to join this distinct school. Tinkerers create gadgetry and items that channel the new fusion of machine and magic, referred to as Technology. They create fantastic items with a wide range of applications, though usually in an experimental nature.
Craft tasks require you to make the items after you get the quest. The best way to do this is to bring a load of the raw material to a trainer next to a refining machine, get the quest, make the item, greet the trainer (turn in), get the quest, and so on until the material is used up. Salvage quests work the same way.
Report tasks are delivery quests designed to show you where the Quartermasters are.