Art ,means ,knowledge in a backward path

Art,means,knowledge in a backward path I notice that much knowledge is useless for applications,so I like to know from you experts their personal experience organized from last to first
activity you learned.In other words: 1)A thing you can do as expert (level 0) 2)Means and knowledge you use immediately at work(i.e.ground matter?!) 3)Means and knowledge to reach level2. 4)So on...
In my case: Level 0:I can build microcomputers for process control. Level1 :I need: 1.1 Using a microcontroller 1.1.1 Searching for electronic manifacturers ads(Motorola ,Siemens,Nec ...) 1.1.2 Studing manifacturer's data book.
1.2 Using peripherals 1.2.1 Searching for electronic manifacturers ads(Motorola ,Siemens,Nec ...) 1.2.2 Studing manifacturer's data book.
1.3 Connecting them 1.3.1 A schematic software (Orcad ,Protel,...) 1.3.2 Interfacing theory (Wolf:Modern VLSI Design Physics(Purcell:Phisics of Berkely)
1.4 Making printed circuit board 1.4.1 A PCB software(Orcad...) 1.4.2 A Bromograph 1.4.3 Chemical solutions for carving .
Instead of an activity tree ,also appreciated is a description of pratical means and pratical theory books Is there some similiar discussion about this science ,on the Web? Thanks A science Amateur.
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