The Cooktop does not light.

There is no power. Ensure the cooktop is plugged in and there is power to the wall socket.
There is no gas. Ensure the gas supply valve is turned on and the supply to the house is working. The gas should be heard when a burner is turned on.
The gas igniters are dirty. Clean with a toothbrush and methylated spirits.
The burner parts are not properly located. Ensure the cooktop has been assembled correctly and the burner cap is sitting flat.