How do I add blocks

I'm trying to make a charcoal block datapack and I already have the texture for the block and the pack.mcmeta file I just need to know how to create one, preferrably without using entities but if I have to use entities for it to work properly then I'm hoping it could be seamless and subtle, I want to make it have the same properties as a coal block, so I'm wondering how I'm supposed to make it a fuel item