Hi rambler-
It’s usually made with four 4.5 x 5.5” pieces, available as a set for $25 under the Kits and Materials tab > Hardware subtab.
Sometimes people add a fifth piece across the front from the top to half height which increases stability and heat reflectivity at a cost of a little weight and ease of loading. I don’t use the fifth piece.
The blow tube, as described in the Nimblewill article, works well and is worth the small increase in weight. Or, if you carry a hydration system, you could probably dual-use the tube to save a little weight.
There is no consensus at this point as to if the side air slots are of benefit or not. Mine uses the slots, other folks report good results without slots as well. I think if I were to make another one I would leave out the slot on the back side so that end can be faced into the wind to reduce sparking.
Nice little stove.
AYCE