A tabletop convection oven blows heated air through its interior to cook the food. This enables the heat to penetrate the food being cooked in a more even fashion than if the heat was emanating from a single source, such as the heating element of a conventional oven. Cooking food in a convection oven requires adjusting the timing as compared to non-convection ovens. This adjustment should only be done if you are sure that the oven being used is a convection oven. There are a number of ways to verify this, none of which requires any tools or any disassembling of the oven in question.
The specifications for the oven will detail whether the parts inside are that of a convection oven. Look in the specifications section of the oven's manual. If you see a fan listed in the specifications, the oven is a convection oven. If there is no fan listed, this is the manual for a non-convection oven.
Listen for the sound of the fan that signifies the oven is a convection oven. Adjust the oven's control to any cooking setting. Turn the oven on. Place your ear next to a side of the oven where there is a vent -- the oven will not be hot yet and so you will not be pained by any heated air coming out. If you hear the whirring sound of a fan, the oven is a convection oven.
Air being forced out of the grill on the side of the oven signifies the presence of an internal fan that is a part of a convection oven. Set the oven's control to the "Medium" setting. Turn the oven on. Place your hand a few inches away from one of the grills on the side of the oven. Feel the breeze from the air being forced out of the grill that lets you know this is convection oven.