Not sure where to start? Here's the order.
The system works best as a set, and the Basket is always the first piece. It lifts charcoal off the grill floor so air can move, burns stay cleaner, and cleanup takes seconds. Add the Can and it catches the ash so Dad never has to dig. Add the Divider and he can run two heat zones at once, direct and indirect, without rearranging coals mid-cook.
Buying just the Can without the Basket is a common miss. The Can is designed to work with the Basket. Without it, Dad still has to lift the grate, move the charcoal by hand, and empty ash the old way. Start with the Basket, or skip straight to the bundle and give him the whole setup.