It depends on a few things, like which CAD suite do you want to learn (I recommend KiCad because it's FOSS and I have a soft spot for it) and the second would be what kinda direction do you want to go? Analog, Digital, Mixed SIgnal? High Speed?
For just the basics, that's a good question! I don't know of any really good resources out there, I personally picked it up by just flailing around and asking my wife for help and a lot of googling.
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