I want to use Emacs multiple cursors, but I don't know how to set it up.

I was able to install the multiple cursors of emacs, but I'm having trouble because I don't know the settings after that.In which file should I write require?

I can't find a website that describes that area in detail.You may not know that, but I appreciate your cooperation.

The following is described in ~/.emacs

;; key bind(load-theme'manoj-darkt) (define-key global-map[(Sc)]
'kill-ring-save)

;; package init (require'package) (add-to-list'package-archives
) '("melpa"."https://melpa.org/packages/")t) (package-initialize)

(custom-set-variables;; custom-set-variables were added by Custom.
;; If you edit it by hand, you could message up, so be careful.;;
Your init file should contain only one such instance.;; If there is
more than one, they won't work right.' (package-selected-packages
) (quote(multiple-cursors))(custom-set-faces;; custom-set-faces
was added by Custom.;; If you edit it by hand, you could message up,
so be careful.;; Your init file should contain only one Such
instance.;; If there is more than one, they won't work right.)

(require' multiple-cursors)
(global-set-key(kbd "C-S-c C-S-c")'mc/edit-lines)
(global-set-key(kbd "C->")'mc/mark-next-like-this)
(global-set-key(kbd "C-<")'mc/mark-previous-like-this)
(global-set-key(kbd "C-c C-<")'mc/mark-all-like-this)

I don't know if it is required.
If you press ctrl+Shift+c→ctrl+Shift+c, nothing will respond