Q: My,desktop,Mac,,,vintage,2006,,replaced,by,Masco,Pro,(Retina,,15-inch,,Mid,2015)

Where can I buy a book , recommended by Mac operator in large store, who sell Macs, called OS X El Capitan for "NULS".

     Much of the system has changed..... e.g.  presentation of "Mail"  etc      To name but one of several

     My first Mac dates from 1986, I have had others during the last 30 years, no problem.

     I wish to sit with the new Mac and familiar myself with what is different and resume what I do as simply as possible.

          many thanks,,         Eric Dalzell