All about the essential and item mechanics. The redstone stuff is pretty easy to comprehend, haven't started into these tho as i know nothing other then they move them, but not the mechanics of how It works.
Well I can tell you about the essentia. It comes from the blue brain, obviously. You set it up as shown in the Thaumonomicon and then you link it to your essentia jars using one or more Crystalline Eyes. There are limits to this - you can only link one eye and eight jars at a relatively small range with the minimum setup, but you can also increase these limits by adding additional blue crystal clusters around the essentia locus construct. With enough clusters, you could probably get the range up to about 256 blocks if not more, and plenty of eyes and jars. The crystalline eyes will link to any attached jars, just like golems do, so you shouldnt need more than one or two of them for most builds.
The structure by itself only allows you to monitor the amounts of essentia stored, which you can do manually by mousing over the brain, or through vis readers, also from automagy... which should allow you to automate things (and which I have not gotten into).
To add the ability of the structure to function as an essentia distribution point, you add the essentia aggregator block. You can see how I used it in my build, but you can also use it in combination with essentia mirrors.
P.S. - I originally had plans to use the essentia pump from witching gadgets in conjunction with this in order to do a lot more around my base, but couldnt get the pump to work. It would consistently fail to recognize the suction in the attached system, as it's supposed to.. and therefore never pulled essentia from mirrors. If anyone knows how to make that thing work, that'd be cool