You need to rotate the wood/tray/tube and this will dump the wood chips onto the heat elements, the chips/chunks will burn down to ash.
I'm another MES owner - 40". You shouldn't need to do anything special, no foil is required in fact it will cause problems with the MES, the same with any lava rocks. There simply isn't any room in the small heating element/wood chamber.
The wood tray/tube, can hold about about 2 cups of wood chips, personally I only use about 2/3 cup at a time, the owners manual says use no more than one cup.
Currently I start with a 2/3 cup of wet wood chips, after they get going I then pull the wood/tray/tube out and put in a couple of wood chunks and replace the tube. The reason I pull the tube, if you load chunks that may be too big when dumped they may jam and prevent the tube from being able to pull out. I get around 1 hour of visible smoke this way. Notice the word visible, there is residual smoke still in the chamber even though the wood is consumed, the ash is still smoldering and the cooking area is most likely filled with smoke. I allow about 30 minutes for residual smoke to still be flavoring the meat, so on my 2/3 cup wood chip then 2 or 3 wood chunks I get about 1.5 hours of smoking, however I try to add either more chunks or chips every hour or so. You have to be careful about putting too much wood in the MES and generating creosote.