Genuine Toshiba owner's manual. Couldn't really ask for more. And written in understandable English in contrast to a few recent experiences I have had with manuals for other equipment other than Toshiba but made in China and written in "Chinglish"!
Text excerpt from page 15 (click to view)
The gas top oven
Before you use the oven you should wipe it out with a damp cloth to remove any dust. You can only cook on one shelf at a time. You should turn food round during the cooking time.
The shelf in the top oven is different from the shelves in the main oven. You can distinguish the top oven shelf from the main oven shelves because it has a metal plate attached to it. The shelves provided for the main oven should only be used in the main oven. Similarly, only use the top oven shelf in the top oven. Shelf positions are counted from the top downwards. Most top oven cooking should be carried out using the shelf provided in shelf position 2. However, when cooking a small joint or a deep cake you can use the top oven shelf on the base of the top oven to allow enough air to circulate around the food. Shelf on base
For best results we recommend open roasting, with or without a trivet using minimal fat or oil to prevent splashing. It is not necessary to cover meat or poultry or wrap food in foil when roasting as this restricts the circulation of heat and will lead to extended cooktimes. If you are using a roasting bag or cover chicken breast with foil, be prepared to allow an extra 10 - 15 minutes for each 1/2kg (1lb). When cooking large items such as turkeys, the use of foil may be required to prevent the breast becoming dry before the rest of the bird is fully cooked. 15