How to light the pilot for an old Gas Heater
Call the gas company.  

If they aren't also the power company and there isn't a power crisis like a wind storm, then they'll often send someone out to light it for you for free. 

The gas company's perspective is they would much rather make a service call than have you attempt to light it and fail (e.g. Due to an obsolete or defective valve) and blow your house up.  That also lets them put eyes on your setup, do a safety check, and give you advice if you need it.  If they have conservation incentive programs that your unit qualifies for, they can have that conversation with you too.