Superb guide, one question i do have, is regarding the numbers in rectangles. The CFD guide Breezy Pete uploaded, says that they are "Reference to continuation of wiring - Number in a frame indicates the current path in which the wiring is continued"
Purely as an example, looking at the fuel sender for a 2005 Mk2 Octavia 1.9TDI, section 8/14, diagram number S97-4743. The schematic shows three wires shown with numbers in rectangles, 206, 207 and 210. I cannot find any other references to 207 and 210 anywhere else, I can find 206, but that goes directly to a fuse which is marked with an asterisk saying it is only fitted on vehicles with Extended Service Intervals (ESI), obviously for a fuel sender, that is nonsense.
What am i missing? My question is specifically about following the schematic path hence replying to this thread rather than fault finding an Octy, otherwise sorry for the bump.