If you are smelling gas then this is an emergency situation.
First of all open the windows.Let the air out. Secondly : Check the Burners, if they are open, then switch off by using the knob. Thirly, If you still smell gas, then close the knob of the main gas cylinder.
This might mean there is leakage in your pipe, Call the service center numbers.
I will suggest you keep some freelancers phone number who does work with the gas stoves. This will come in handy.