Select the Project Specific table. Click the file browser button below the table. You need to find where the official KiCad libraries are installed on your computer. Look for a library directory containing a hundred of .dcm and .lib files. Try in C:\Program Files (x86)\KiCad\share\ (Windows) and /usr/share/kicad/library/ (Linux). When you have found the directory, choose and add the ‘MCU_Microchip_PIC12.lib’ library and close the window. It will be added to the end of of the list. Now click its nickname and change it to ‘microchip_pic12mcu’. Close the Symbol Libraries window with OK.
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I found there was no folder “library”, and most of the folders under “kicad” were empty, how to fix this?
I think they are following the v5 getting started guide, which seems to have you add the MCU_Microchip_PIC12 library from the official libraries to the project-specific library table.