How to choose between those labels?
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If that does not work, you may have to install the documentation as a separate package, or go get the manuals from the KiCad website, where you can choose between reading online, or downloading in html, pdf, or epub format.
On a single sheet you can use either net or global labels.
(If you use hierarchical labels the ERC starts complaining).
If your schematic consists of multiple sheets, then the difference is a lot bigger:
- Net labels only connect on the same sheet.
- Global labels connect globally (across all sheets).
- Hierarchical labels connect within sheet borders and to the hierarchical sheet boxes, where the labels can be imported from the underlying schematic.
If you’re more of a do-er then a reader, then just put some labels on a schematic with a few dummy components, import the components & netlist into Pcbnew and see for yourself what connects to what.
This might be a good read for you Hierarchical or flat schematic design, what is best for me? (How to deal with multi page schematics?)