Coal by itself is hard to start burning. You need to heat that "green" coal up to drive off lots of the chemically bonded gasses inside it - leaving you with just the carbon fuel - called coke. Just like turning wood down into just coals - leaving you with charcoal, you do the same with coal to get coke. And that coke is then much easier to start burning. You will see the difference between green coal and coke. It is about half the weight, more gray colored, and crumbles easier than coal. But it is now mostly pure carbon fuel for your fire - with few impurities left in it. So when you have your coal fire going, you should always save some of the coked out coal to help you in starting the next fire. Just push some of the "coals" off to the side and they will go out.
To start a coal fire, you basically have to start a small wood/paper fire. Crumpled up newspaper or shredded strips of cardboard to start the fire, with small sticks of wood on top - with your coal piled up around the outside. As your "wood" fire starts burning, place some of your coked out coal on top. Or put some small pieces of green coal on top. The heat will start baking out those "gasses" and eventually get the coal to burning. That coked out coal just starts burning a lot sooner and easier. And the smaller the bits of green coal, the easier they are to get burning. Once you get some of the coal/coke burning, slowly start adding more chunks to get more of a fire going. And then start adding more green coal up the sides and over the top. All that Smoke you see is the heat driving off those "gasses" and getting your coal to that coke stage where it will burn.
As you get your fire going and start adding more green coal on top, you will also see that the green coal is having some "oils" baked out of it. This helps pack/bind together that coal to create a layer that covers over your fire and helps hold the heat inside. And that extra heat also them helps turn that green coal layer into coke to burn.
So start a small wood/paper fire first to then get your coal fire burning. Otherwise you are relying upon that lighter fluid to burn long enough to then get your coal burning. That can some time, but goes faster with that already coked out coal.
And every now and then I get frustrated and just pick up the gas torch and blast the coal/coke in the forge until I get it going enough! Some days the coal fire just doesn't want to start, but I never take the "hint" and go do something else.
Mikey - that grumpy ol' German blacksmith out in the Hinterlands