There could be a couple of issues preventing your heater working .Firstly have someone explain to you how it works, face to face. I would think that knowing how to re-light the pilot might be a good start. Also a service to check out the thermocouple which retains the pilot flame might be a good idea.These heaters are not self maintaining but can be dangerous,far more than boilers that have better fault detection,have it checked out and get some instruction the same time.
Guytawe
June 2010