How do kilns work

[Dill]

Do i just put fuel (sticks) in it untill the bar is full then light it?

[TeckXKnight]

You don't need it to be full. Just a few sticks is often enough to bake whatever you have in there. Different items require different amounts of fuel. I believe you can find exact fuel requirements on the wiki, let me double check that.

Edit: http://ringofbrodgar.com/wiki/Kiln
And each individual page will tell you how much fuel it needs. Remember that you only need as much fuel in the kiln as the longest burning item. If you are making 20 bricks and an earthen ware platter. Bricks require 2 branches while Earthen Ware requires 4 branches. Therefore you only need to put 4 branches of fuel in the kiln.

[DDDsDD999]

There is of course the fuel bug where you put the items in the kiln/oven/smelter, wait for how long it takes to bake it(5 minutes x ticks or branches, and 20 minutes for smelting ore) minus 5 minutes, put a branch in (or coal if smelter) and light it.