If you don't have it, use a search engine to see if you can find an online version of the manual. [title] Press the convection button or turn the dial to convection.
[header] How to preheat a convection oven [title] Read the oven's instruction manual. [step] Convection oven models are different and these steps may differ from the model that you own. Look for the owners or instruction manual that you got with your convection oven.