Arrange the shelves in the required positions before switching the oven on. Shelf positions are numbered from the top downwards. Ensure that food is placed centrally on the shelf and there is sufficient room around the baking tray/dish to allow for maximum circulation. Do not push dishes too far back as food will burn if it overhangs the burner flame. Stand dishes on a suitably sized baking tray on the shelf to prevent spillage onto the oven base and to help reduce cleaning. The material and finish of the baking tray and dishes used affect base browning. Enamelware, dark, heavy or non-stick utensils increase base browning. Shiny aluminium or polished steel trays reflect the heat away and give less base browning. When cooking more than one dish in the oven, place dishes centrally on different shelves rather than cluster several dishes on one shelf, this will allow the heat to circulate freely for the best cooking results. If you are cooking more than one tray of similar items, for example cakes or biscuits, swap the trays during cooking or you can remove the top tray when the food is cooked and move the lower tray to the higher shelf to finish cooking. Do not place baking trays directly on the oven base as it interferes with the oven air circulation and can lead to base burning; use the lower shelf position. Do not place cookware and cooking pots with rough bases e.g. cast iron on the oven door as damage to the glass may occur.