elisp - Changing key bindings in emacs -

i want change commands setting bookmarks, listing them , finding them in emacs. emacs lisp code have tried:

(global-set-key (kbd "c-c c-z") (kbd "c-x r m")) 

this failing. correct method?

if want define key other key does, want do

(global-set-key (kbd "c-c c-z") (global-key-binding (kbd "c-x r m"))) 

if can rebind c-x r m else , c-c c-z still bound bookmark-set (this similar file copying).

if, on other hand, want make c-c c-z alias c-x r m, need use function-key-map:

(define-key function-key-map (kbd "c-c c-z") (kbd "c-x r m")) 

in case c-c c-z doing whatever c-x r m doing if rebind latter (this similar symbolic file links).