Easiest way to transfer my library from iTunes Match to External Hard Drive

I am confused by Apple Music (which I've never used) & iTunes Match (which is all I have left after iTunes got turned into Music). How can I copy all my music from iTunes Match to an external hard drive? I really don't know what I'm doing at all... My iTunes Match stuff is voluminous and was ripped from my CD collection going back 20 years. It would not fit on my Mac if it had to be downloaded there before moving it to the external drive. Talk to me like I'm in kindergarten please... -M