I'm sure it's a silly question, but what are the steps needed to ship an order from the admin? I'm assuming at the very least the payment needs to be captured, but in some of my testing the button shows up when I would expect (after approving the order) and in some it doesn't show up and I need to "split" it first. Even if it's a single item and the only item in the order, there are some times I have to split it.