copied CD's to music folder via itunes can not add to ipod

I copied 4 old CD's to computer via iTunes today, added them to my playlist but when I drag playlist to iPod, the songs I added today are not included in the playlist on the iPod. I even deleted old files from the iPod thinking it was a storage issue ... with all the new changes and me being stuck in the 50's, can someone please point out to me where I went wrong? THANKS!!