Check /usr/share/doc/cvs/html-cvsclient, /usr/share/doc/cvs/html-info, /usr/share/doc/cvsbook with lynx or run info cvs and man cvs for detailed information.
/usr/share/doc/cvs/html-cvsclient
/usr/share/doc/cvs/html-info
/usr/share/doc/cvsbook
lynx