My method to get natural coal working:
Just light the coal.
Then put one above the other.
After this you put a Chimney (made of aluminium foil) over it.
Then you wait a couple of minutes till the coal glows completely.
The principe is that a heat is reflected and so on^^
(I am not good in describing things in english
The chimney is is easy to make.
You just need a 0,33l bottle, like this one:
And then you wrap the aluminium foil around it.
Hope you understand me :>