The heat distribution plates were developed to distribute the heat as evenly as possible over the grid of your gas barbecue.
For the Barbecook Spring and Siesta you need to place the burner caps in the provided slots, above the round burners.
For the Barbecook Stella the burner caps should be placed above the flat burners, also in the provided slots. The side of the burner cap with the two openings is the front and must therefore be placed forward.