Hello Ben,, welcome to the forum.
Read this thread: Converting from wood
There are very similar questions asked and some links to sites and a few answers for you..
For a rough answer, to burn anthracite, all combustion air must come up through the coal bed, the coal will not burn from air above the coal bed. So a coa grate has to be designed into the stove, with a shaker mechanism to agitate the coal bed and get the ash to fall down through the grates into an ashpan.
Take a look at some of the photos and cutaway drawings in the provided links.. you wll see what I'm describing
Hope this helps.