What happened to the music I copied off my purchased cds into my iTunes library 10 years ago?

I had purchased tons of cds a long, long time ago. I still have them but I copied them into my computer about 10 years ago when CD burners and copiers were still the current technology. I don’t see any of that music in my library, only the music I have purchased. I still own two old original ipods and they still work (for now) but I want to get that music copied into my new computer (MacBook Pro) music library. Anyone have any help? I have been doing research and think an external CD player/burner, reader may be the answer. I still have a back up of the ITunes library from 2010. I simply want to be able to preserve the music that I spent years on getting into my library. Thanks!