Don't know that heater but you say it has an electronic ignition. That tells me it has to be wired to the AC line, not a manual spark ignitor. The manual spark ignitors, as on gas grills, are a snap action type...the snap is very obvious and they produce a momentary spark. That red button may be the pilot valve override that is used to get the pilot going and keep it on until a thermopile heats up and produces enough power to keep the pilot valve open. If the heater is not connected to the AC 120 volt line then it is a 'millivolt' system as described in the previous sentence. Whatever the system you may have air in the gas line too that needs to be purged before the pilot will light. As Pat said, calling the company is the best idea and they should clear things up easily.
Al