You will need to expense stock and non-stock items differently for jobs so that the cost of items is applied correctly toward a job.
When you purchase a non-stock, service, or labor type of item, you can enter the item using the Purchases or Payments windows and assign the expense for the item to a job at the same time.
When you use a stock item, you need to cost the item, so you should adjust inventory for the usage of that item. If the stock item has not been entered into inventory yet, you will first need to enter the item in inventory, as well. For any stock item you can use either method of expensing:
Or,