what's the best coal to buy or will any do ? I've had some before but it pops not sure what it was now
If you are an amateur having a go then anything you get for example from a petrol station will do.
The trick is what you do with it. It wont work properly in big lumps. It has to be crushed into about 20 - 30 mm pieces so it provides a nice bed of heat.
Im an amateur / hobbyist. I was luck enough to have a lesson from @jullianthegypsy its awesome what can be achieved with simple gear and and a lot of knowledge