any pointers.?
nope.
It may pay to learn how to rolling hop comfortably and accurately so you can get onto the handrail easily.
yeah, its not like i can sif hop onto it.
Its hard and you need to land on the pedal only to avoid hook ups that will throw you off. I still can’t get them yet, ledges and stuff is not much of a problem as you can use your crank to grind also but landing and holding pedal only is difficult.
Just watch a few videos you’ll see how everyone grinds rails on just pedal, in fact watch this video you can see him grinding rails on pedal ledges on pedal and crank. He is quite good though 
you could learn to grind a box first?
i can already grind benches boxes homemade rails down stairs etc. just not a proper rail. can i use my cutting board to stop my pedal from sticking
Find a skate park, and start there.
They usually have low rails to grind, so falling wont hurt to bad, and getting to do the grind wont be so risky.
Really though, just go for it, and land with lots of weight on the grinding foot. Too much weight on the other pedal can lose your balance, or twist the wheel.