Emacs step by step

01-init.el

;; This buffer is for text that is not saved, and for Lisp evaluation.
;; To create a file, visit it with C-x C-f and enter text in its buffer.
;; This is a import that ships with emacs.
;; package is Emacs's package manager.
(require 'package)

;; Emacs has an official repository of packages and a more current
;; unofficial one. Melpa is the 'unoffical one' (which in this
;; case translates to more up to date, newer, and by extension,
;; a bit more volatile). The official repo is called org. This
;; repo is slow changing and extremely stable (but doesn't have
;; all the cool/cutting edge packages that are being used).
(push '("melpa" . "http://melpa.org/packages/") package-archives)
(push '("org" . "http://orgmode.org/elpa/") package-archives)
(push '("melpa-stable" . "https://stable.melpa.org/packages/") package-archives)

;; After the repositories have been set, initialize the package
;; manager.
(package-initialize)

(unless package-archive-contents (package-refresh-contents))
(unless (package-installed-p 'use-package) (package-install 'use-package))

(use-package evil
  :ensure t
  :init
  (setq evil-want-C-i-jump nil)
  :config

  (evil-mode 1))

02-init.el

;; This buffer is for text that is not saved, and for Lisp evaluation.
;; To create a file, visit it with C-x C-f and enter text in its buffer.
;; This is a import that ships with emacs.
;; package is Emacs's package manager.
(require 'package)

;; Emacs has an official repository of packages and a more current
;; unofficial one. Melpa is the 'unoffical one' (which in this
;; case translates to more up to date, newer, and by extension,
;; a bit more volatile). The official repo is called org. This
;; repo is slow changing and extremely stable (but doesn't have
;; all the cool/cutting edge packages that are being used).
(push '("melpa" . "http://melpa.org/packages/") package-archives)
(push '("org" . "http://orgmode.org/elpa/") package-archives)
(push '("melpa-stable" . "https://stable.melpa.org/packages/") package-archives)

;; After the repositories have been set, initialize the package
;; manager.
(package-initialize)

(unless package-archive-contents (package-refresh-contents))
(unless (package-installed-p 'use-package) (package-install 'use-package))

(use-package evil
  :ensure t
  :init
  (setq evil-want-C-i-jump nil)
  :config

  (evil-mode 1))

(defun say-hello-world ()
  (interactive)
  (insert "hello world"))

03-init.el

;; This buffer is for text that is not saved, and for Lisp evaluation.
;; To create a file, visit it with C-x C-f and enter text in its buffer.
;; This is a import that ships with emacs.
;; package is Emacs's package manager.
(require 'package)

;; Emacs has an official repository of packages and a more current
;; unofficial one. Melpa is the 'unoffical one' (which in this
;; case translates to more up to date, newer, and by extension,
;; a bit more volatile). The official repo is called org. This
;; repo is slow changing and extremely stable (but doesn't have
;; all the cool/cutting edge packages that are being used).
(push '("melpa" . "http://melpa.org/packages/") package-archives)
(push '("org" . "http://orgmode.org/elpa/") package-archives)
(push '("melpa-stable" . "https://stable.melpa.org/packages/") package-archives)

;; After the repositories have been set, initialize the package
;; manager.
(package-initialize)

(unless package-archive-contents (package-refresh-contents))
(unless (package-installed-p 'use-package) (package-install 'use-package))

(use-package evil
  :ensure t
  :init
  (setq evil-want-C-i-jump nil)
  :config

  (evil-mode 1))

(use-package osx-clipboard
  :ensure t
  :config
  (osx-clipboard-mode 1))

(use-package evil-leader
  :ensure t
  :config
             
  (defun say-hello-world ()
     (interactive)
     (evil-normal-state)
     (evil-goto-line)
     (evil-open-below 1)
     (evil-normal-state)
     (insert "hello world"))

  (global-evil-leader-mode)
  (evil-leader/set-leader ",")
  (evil-leader/set-key
    "h" 'say-hello-world))