(require 'ox-latex)
(setq-local
 org-latex-classes
 '(("chapter-code"
    "\\documentclass{chapter-code}"
    ("\\chapter{%s}" . "\\chapter*{%s}")
    ("\\section{%s}" . "\\section*{%s}"))))

(setq org-latex-hyperref-template "
\\hypersetup{\n pdfauthor={%a},\n pdftitle={%t},\n pdfkeywords={%k},
 pdfsubject={%d},\n pdfcreator={%c},\n pdflang={%L},\n colorlinks=true}\n")

(local-set-key
 (kbd "C-c t")
 (lambda nil
   (interactive)
   (save-match-data
     (let ((string (buffer-string))
           (pos 0)
           (tag 0))
       (while (string-match "<<tag:\\([0-9]+\\)>>" string pos)
         (setq tag (max tag
                        (string-to-number (match-string 1 string)))
               pos (match-end 0)))
       (insert "<<tag:" (number-to-string (1+ tag)) ">>")))))